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2020-03-17Merge branch 'for-5.7-console-exit' of ↵Greg Kroah-Hartman1-0/+1
git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk into tty-next We need the console patches in here as well for futher work from Andy. * 'for-5.7-console-exit' of git://git.kernel.org/pub/scm/linux/kernel/git/pmladek/printk: console: Introduce ->exit() callback console: Don't notify user space when unregister non-listed console console: Avoid positive return code from unregister_console() console: Drop misleading comment console: Use for_each_console() helper in unregister_console() console: Drop double check for console_drivers being non-NULL console: Don't perform test for CON_BRL flag Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-11console: Introduce ->exit() callbackAndy Shevchenko1-0/+1
Some consoles might require special operations on unregistering. For instance, serial console, when registered in the kernel, keeps power on for entire time, until it gets unregistered. Example of use: ->setup(console): pm_runtime_get(...); ->exit(console): pm_runtime_put(...); For such cases to have a balance we would provide ->exit() callback. Link: http://lkml.kernel.org/r/20200203133130.11591-7-andriy.shevchenko@linux.intel.com To: linux-kernel@vger.kernel.org To: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Signed-off-by: Petr Mladek <pmladek@suse.com>
2020-01-21sparc/console: kill off obsolete declarationsArvind Sankar1-2/+0
commit 09d3f3f0e02c ("sparc: Kill PROM console driver.") missed removing the declarations of the deleted prom_con structure and prom_con_init function from console.h. Kill them off now. Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu> Signed-off-by: David S. Miller <davem@davemloft.net>
2019-05-18panic: add an option to replay all the printk message in bufferFeng Tang1-1/+6
Currently on panic, kernel will lower the loglevel and print out pending printk msg only with console_flush_on_panic(). Add an option for users to configure the "panic_print" to replay all dmesg in buffer, some of which they may have never seen due to the loglevel setting, which will help panic debugging . [feng.tang@intel.com: keep the original console_flush_on_panic() inside panic()] Link: http://lkml.kernel.org/r/1556199137-14163-1-git-send-email-feng.tang@intel.com [feng.tang@intel.com: use logbuf lock to protect the console log index] Link: http://lkml.kernel.org/r/1556269868-22654-1-git-send-email-feng.tang@intel.com Link: http://lkml.kernel.org/r/1556095872-36838-1-git-send-email-feng.tang@intel.com Signed-off-by: Feng Tang <feng.tang@intel.com> Reviewed-by: Petr Mladek <pmladek@suse.com> Cc: Aaro Koskinen <aaro.koskinen@nokia.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Kees Cook <keescook@chromium.org> Cc: Borislav Petkov <bp@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-31console: Replace #if 0 with atomic var 'ignore_console_lock_warning'Thomas Zimmermann1-5/+9
The macro WARN_CONSOLE_UNLOCKED prints a warning when a thread enters the console's critical section without having acquired the console lock. The console lock can be ignored when debugging the console using printk, but this makes WARN_CONSOLE_UNLOCKED generate unnecessary warnings. The variable ignore_console_lock_warning temporarily disables WARN_CONSOLE_UNLOCKED. Developers interested in debugging the console's critical sections should increment it before entering the CS and decrement it after leaving the CS. Setting ignore_console_lock_warning is only for debugging. Regular operation should not manipulate it. Acknoledgements: This patch is based on an earlier version by Steven Rostedt. The use of atomic increment/decrement was suggested by Petr Mladek. Link: http://lkml.kernel.org/r/717e6337-e7a6-7a92-1c1b-8929a25696b5@suse.de Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Acked-by: Hans de Goede <hdegoede@redhat.com> Acked-by: Petr Mladek <pmladek@suse.com> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Andrew Morton <akpm@linux-foundation.org> [b.zolnierkie: use <linux/atomic.h>] Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
2018-06-28console/fbcon: Add support for deferred console takeoverHans de Goede1-0/+5
Currently fbcon claims fbdevs as soon as they are registered and takes over the console as soon as the first fbdev gets registered. This behavior is undesirable in cases where a smooth graphical bootup is desired, in such cases we typically want the contents of the framebuffer (typically a vendor logo) to stay in place as is. The current solution for this problem (on embedded systems) is to not enable fbcon. This commit adds a new FRAMEBUFFER_CONSOLE_DEFERRED_TAKEOVER config option, which when enabled defers fbcon taking over the console from the dummy console until the first text is displayed on the console. Together with the "quiet" kernel commandline option, this allows fbcon to still be used together with a smooth graphical bootup, having it take over the console as soon as e.g. an error message is logged. Note the choice to detect the first console output in the dummycon driver, rather then handling this entirely inside the fbcon code, was made after 2 failed attempts to handle this entirely inside the fbcon code. The fbcon code is woven quite tightly into the console code, making this to only feasible option. Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
2018-02-27console: Fill in struct consw argument namesKees Cook1-26/+32
Reading the function declarations for the console callbacks lacks any hints as to what the arguments are. Instead of going and digging around in various implementations that may each only have a subset of the callbacks, name all the arguments in the declaration. This has no functional change. Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-04-18console: move console_init() out of tty_io.cNicolas Pitre1-0/+2
All the console driver handling code lives in printk.c. Move console_init() there as well so console support can still be used when the TTY code is configured out. No logical changes from this patch. Signed-off-by: Nicolas Pitre <nico@linaro.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2017-01-25console: Add callback to flush scrollback buffer to consw structManuel Schölling1-0/+4
This new callback is in preparation for persistent scrollback buffer support for VGA consoles. With a single scrollback buffer for all consoles, we could flush the buffer just by invocating consw->con_switch(). But when each VGA console has its own scrollback buffer, we need a new callback to tell the video console driver which buffer to flush. Signed-off-by: Manuel Schölling <manuel.schoelling@gmx.de> Reviewed-by: Andrey Utkin <andrey_utkin@fastmail.com> Tested-by: Andrey Utkin <andrey_utkin@fastmail.com> Tested-by: Adam Borowski <kilobyte@angband.pl> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-12-13Merge tag 'tty-4.10-rc1' of ↵Linus Torvalds1-5/+11
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty Pull tty/serial updates from Greg KH: "Here's the tty/serial patchset for 4.10-rc1. It's been a quiet kernel cycle for this subsystem, just a small number of changes. A few new serial drivers, and some cleanups to the old vgacon logic, and other minor serial driver changes as well. All of these have been in linux-next for a while with no reported issues" * tag 'tty-4.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (54 commits) serial: 8250_mid fix calltrace when hotplug 8250 serial controller console: Move userspace I/O out of console_lock to fix lockdep warning tty: nozomi: avoid sprintf buffer overflow serial: 8250_pci: Detach low-level driver during PCI error recovery serial: core: don't check port twice in a row mxs-auart: count FIFO overrun errors serial: 8250_dw: Add support for IrDA SIR mode serial: 8250: Expose set_ldisc function serial: 8250: Add IrDA to UART capabilities serial: 8250_dma: power off device after TX is done serial: 8250_port: export serial8250_rpm_{get|put}_tx() serial: sunsu: Free memory when probe fails serial: sunhv: Free memory when remove() is called vt: fix Scroll Lock LED trigger name tty: typo in comments in drivers/tty/vt/keyboard.c tty: amba-pl011: Add earlycon support for SBSA UART tty: nozomi: use permission-specific DEVICE_ATTR variants tty: serial: Make the STM32 serial port depend on it's arch serial: ifx6x60: Free memory when probe fails serial: ioc4_serial: Free memory when kzalloc fails during probe ...
2016-11-11Revert "console: don't prefer first registered if DT specifies stdout-path"Hans de Goede1-6/+0
This reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path"). The reverted commit changes existing behavior on which many ARM boards rely. Many ARM small-board-computers, like e.g. the Raspberry Pi have both a video output and a serial console. Depending on whether the user is using the device as a more regular computer; or as a headless device we need to have the console on either one or the other. Many users rely on the kernel behavior of the console being present on both outputs, before the reverted commit the console setup with no console= kernel arguments on an ARM board which sets stdout-path in dt would look like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 tty0 -WU (E p ) 4:1 Where as after the reverted commit, it looks like this: [root@localhost ~]# cat /proc/consoles ttyS0 -W- (EC p a) 4:64 This commit reverts commit 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") restoring the original behavior. Fixes: 05fd007e4629 ("console: don't prefer first registered if DT specifies stdout-path") Link: http://lkml.kernel.org/r/20161104121135.4780-2-hdegoede@redhat.com Signed-off-by: Hans de Goede <hdegoede@redhat.com> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Rob Herring <robh+dt@kernel.org> Cc: Frank Rowand <frowand.list@gmail.com> Cc: Thorsten Leemhuis <regressions@leemhuis.info> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Tejun Heo <tj@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-10-27tty: vt, cleanup and document con_scrollJiri Slaby1-5/+11
Scrolling helpers scrup and scrdown both accept 'top' and 'bottom' as unsigned int. Number of lines 'nr' is accepted as int, but all callers pass down unsigned too. So change the type of 'nr' to unsigned too. Now, promote unsigned int from the helpers up to the con_scroll hook which actually accepted all those as signed int. Next, the 'dir' parameter can have only two values and we define constants for that: SM_UP and SM_DOWN. Switch them to enum and do proper type checking on 'dir' too. Finally, document the behaviour of the hook. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Thomas Winischhofer <thomas@winischhofer.net> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: <linux-fbdev@vger.kernel.org> Cc: <linux-usb@vger.kernel.org> Cc: <linux-parisc@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-10-07console: don't prefer first registered if DT specifies stdout-pathPaul Burton1-0/+6
If a device tree specifies a preferred device for kernel console output via the stdout-path or linux,stdout-path chosen node properties or the stdout alias then the kernel ought to honor it & output the kernel console to that device. As it stands, this isn't the case. Whilst we parse the stdout-path properties & set an of_stdout variable from of_alias_scan(), and use that from of_console_check() to determine whether to add a console device as a preferred console whilst registering it, we also prefer the first registered console if no other has been selected at the time of its registration. This means that if a console other than the one the device tree selects via stdout-path is registered first, we will switch to using it & when the stdout-path console is later registered the call to add_preferred_console() via of_console_check() is too late to do anything useful. In practice this seems to mean that we switch to the dummy console device fairly early & see no further console output: Console: colour dummy device 80x25 console [tty0] enabled bootconsole [ns16550a0] disabled Fix this by not automatically preferring the first registered console if one is specified by the device tree. This allows consoles to be registered but not enabled, and once the driver for the console selected by stdout-path calls of_console_check() the driver will be added to the list of preferred consoles before any other console has been enabled. When that console is then registered via register_console() it will be enabled as expected. Link: http://lkml.kernel.org/r/20160809151937.26118-1-paul.burton@imgtec.com Signed-off-by: Paul Burton <paul.burton@imgtec.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Paul Burton <paul.burton@imgtec.com> Cc: Tejun Heo <tj@kernel.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Daniel Vetter <daniel.vetter@ffwll.ch> Cc: Ivan Delalande <colona@arista.com> Cc: Thierry Reding <treding@nvidia.com> Cc: Borislav Petkov <bp@suse.de> Cc: Jan Kara <jack@suse.com> Cc: Petr Mladek <pmladek@suse.com> Cc: Joe Perches <joe@perches.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Rob Herring <robh+dt@kernel.org> Cc: Frank Rowand <frowand.list@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-06-25tty: vt, remove consw->con_bmoveJiri Slaby1-1/+0
It is never called since commit 81732c3b2fede (tty vt: Fix line garbage in virtual console on command line edition) in 3.7. So remove all the callbacks. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Thomas Winischhofer <thomas@winischhofer.net> Cc: linux-usb@vger.kernel.org Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: linux-fbdev@vger.kernel.org Cc: linux-parisc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25tty: vt, consw->con_set_palette cleanupJiri Slaby1-1/+3
* allow NULL consw->con_set_palette (some consoles define an empty hook) * => remove empty hooks now * return value of consw->con_set_palette is never checked => make the function void * document consw->con_set_palette a bit Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Thomas Winischhofer <thomas@winischhofer.net> Cc: linux-usb@vger.kernel.org Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: linux-fbdev@vger.kernel.org Cc: linux-parisc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-06-25tty: vt, consw->con_scrolldelta cleanupJiri Slaby1-1/+7
* allow NULL consw->con_scrolldelta (some consoles define an empty hook) * => remove empty hooks now * return value of consw->con_scrolldelta is never checked => make the function void * document consw->con_scrolldelta a bit Signed-off-by: Jiri Slaby <jslaby@suse.cz> Cc: Thomas Winischhofer <thomas@winischhofer.net> Cc: linux-usb@vger.kernel.org Cc: Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com> Cc: Tomi Valkeinen <tomi.valkeinen@ti.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: linux-fbdev@vger.kernel.org Cc: linux-parisc@vger.kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-05-23Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds1-0/+2
Pull drm updates from Dave Airlie: "Here's the main drm pull request for 4.7, it's been a busy one, and I've been a bit more distracted in real life this merge window. Lots more ARM drivers, not sure if it'll ever end. I think I've at least one more coming the next merge window. But changes are all over the place, support for AMD Polaris GPUs is in here, some missing GM108 support for nouveau (found in some Lenovos), a bunch of MST and skylake fixes. I've also noticed a few fixes from Arnd in my inbox, that I'll try and get in asap, but I didn't think they should hold this up. New drivers: - Hisilicon kirin display driver - Mediatek MT8173 display driver - ARC PGU - bitstreamer on Synopsys ARC SDP boards - Allwinner A13 initial RGB output driver - Analogix driver for DisplayPort IP found in exynos and rockchip DRM Core: - UAPI headers fixes and C++ safety - DRM connector reference counting - DisplayID mode parsing for Dell 5K monitors - Removal of struct_mutex from drivers - Connector registration cleanups - MST robustness fixes - MAINTAINERS updates - Lockless GEM object freeing - Generic fbdev deferred IO support panel: - Support for a bunch of new panels i915: - VBT refactoring - PLL computation cleanups - DSI support for BXT - Color manager support - More atomic patches - GEM improvements - GuC fw loading fixes - DP detection fixes - SKL GPU hang fixes - Lots of BXT fixes radeon/amdgpu: - Initial Polaris support - GPUVM/Scheduler/Clock/Power improvements - ASYNC pageflip support - New mesa feature support nouveau: - GM108 support - Power sensor support improvements - GR init + ucode fixes. - Use GPU provided topology information vmwgfx: - Add host messaging support gma500: - Some cleanups and fixes atmel: - Bridge support - Async atomic commit support fsl-dcu: - Timing controller for LCD support - Pixel clock polarity support rcar-du: - Misc fixes exynos: - Pipeline clock support - Exynoss4533 SoC support - HW trigger mode support - export HDMI_PHY clock - DECON5433 fixes - Use generic prime functions - use DMA mapping APIs rockchip: - Lots of little fixes vc4: - Render node support - Gamma ramp support - DPI output support msm: - Mostly cleanups and fixes - Conversion to generic struct fence etnaviv: - Fix for prime buffer handling - Allow hangcheck to be coalesced with other wakeups tegra: - Gamme table size fix" * 'drm-next' of git://people.freedesktop.org/~airlied/linux: (1050 commits) drm/edid: add displayid detailed 1 timings to the modelist. (v1.1) drm/edid: move displayid validation to it's own function. drm/displayid: Iterate over all DisplayID blocks drm/edid: move displayid tiled block parsing into separate function. drm: Nuke ->vblank_disable_allowed drm/vmwgfx: Report vmwgfx version to vmware.log drm/vmwgfx: Add VMWare host messaging capability drm/vmwgfx: Kill some lockdep warnings drm/nouveau/gr/gf100-: fix race condition in fecs/gpccs ucode drm/nouveau/core: recognise GM108 chipsets drm/nouveau/gr/gm107-: fix touching non-existent ppcs in attrib cb setup drm/nouveau/gr/gk104-: share implementation of ppc exception init drm/nouveau/gr/gk104-: move rop_active_fbps init to nonctx drm/nouveau/bios/pll: check BIT table version before trying to parse it drm/nouveau/bios/pll: prevent oops when limits table can't be parsed drm/nouveau/volt/gk104: round up in gk104_volt_set drm/nouveau/fb/gm200: setup mmu debug buffer registers at init() drm/nouveau/fb/gk20a,gm20b: setup mmu debug buffer registers at init() drm/nouveau/fb/gf100-: allocate mmu debug buffers drm/nouveau/fb: allow chipset-specific actions for oneinit() ...
2016-04-30tty: vt, make color_table constJiri Slaby1-1/+1
This means all ->con_set_palette have to have the second parameter const too now. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2016-03-30vgacon: dummy implementation for vgacon_text_forceDaniel Vetter1-0/+2
This allows us to ditch a ton of ugly #ifdefs from a bunch of drm modeset drivers. v2: Make the dummy function actually return a sane value, spotted by Ville. v3: Because the patch is still in limbo there's no more drivers to convert, noticed by Emil. v4: Rebase once more, because hooray. I'll just go ahead an apply this one later on to drm-misc. Cc: Emil Velikov <emil.l.velikov@gmail.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Reviewed-by: Emil Velikov <emil.l.velikov@gmail.com> Reviewed-by: Alex Deucher <alexander.deucher@amd.com> Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2016-01-16printk: do cond_resched() between lines while outputting to consolesTejun Heo1-0/+1
@console_may_schedule tracks whether console_sem was acquired through lock or trylock. If the former, we're inside a sleepable context and console_conditional_schedule() performs cond_resched(). This allows console drivers which use console_lock for synchronization to yield while performing time-consuming operations such as scrolling. However, the actual console outputting is performed while holding irq-safe logbuf_lock, so console_unlock() clears @console_may_schedule before starting outputting lines. Also, only a few drivers call console_conditional_schedule() to begin with. This means that when a lot of lines need to be output by console_unlock(), for example on a console registration, the task doing console_unlock() may not yield for a long time on a non-preemptible kernel. If this happens with a slow console devices, for example a serial console, the outputting task may occupy the cpu for a very long time. Long enough to trigger softlockup and/or RCU stall warnings, which in turn pile more messages, sometimes enough to trigger the next cycle of warnings incapacitating the system. Fix it by making console_unlock() insert cond_resched() between lines if @console_may_schedule. Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Calvin Owens <calvinowens@fb.com> Acked-by: Jan Kara <jack@suse.com> Cc: Dave Jones <davej@codemonkey.org.uk> Cc: Kyle McMartin <kyle@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-06-25printk: implement support for extended console driversTejun Heo1-0/+1
printk log_buf keeps various metadata for each message including its sequence number and timestamp. The metadata is currently available only through /dev/kmsg and stripped out before passed onto console drivers. We want this metadata to be available to console drivers too so that console consumers can get full information including the metadata and dictionary, which among other things can be used to detect whether messages got lost in transit. This patch implements support for extended console drivers. Consoles can indicate that they want extended messages by setting the new CON_EXTENDED flag and they'll be fed messages formatted the same way as /dev/kmsg. "<level>,<sequnum>,<timestamp>,<contflag>;<message text>\n" If extended consoles exist, in-kernel fragment assembly is disabled. This ensures that all messages emitted to consoles have full metadata including sequence number. The contflag carries enough information to reassemble the fragments from the reader side trivially. Note that this only affects /dev/kmsg. Regular console and /proc/kmsg outputs are not affected by this change. * Extended message formatting for console drivers is enabled iff there are registered extended consoles. * Comment describing /dev/kmsg message format updated to add missing contflag field and help distinguishing variable from verbatim terms. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: David Miller <davem@davemloft.net> Cc: Kay Sievers <kay@vrfy.org> Reviewed-by: Petr Mladek <pmladek@suse.cz> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-03-26console: Add extensible console matchingPeter Hurley1-2/+1
Add match() method to struct console which allows the console to perform console command line matching instead of (or in addition to) default console matching (ie., by fixed name and index). The match() method returns 0 to indicate a successful match; normal console matching occurs if no match() method is defined or the match() method returns non-zero. The match() method is expected to set the console index if required. Re-implement earlycon-to-console-handoff with direct matching of "console=uart|uart8250,..." to the 8250 ttyS console. Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-20vt: delete unneeded function unregister_con_driverWang YanQing1-1/+0
Now there is no place use unregister_con_driver, and we can achieve unregister_con_driver's function with unregister_con_driver easily, so just delete it to reduce code size and duplication. Signed-off-by: Wang YanQing <udknight@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-05-20vt: delete unneeded functions register_con_driver|take_over_consoleWang YanQing1-2/+0
Now there is no place use register_con_driver|take_over_console, and we can achieve their function with do_register_con_driver| do_take_over_console easily, so just delete them to reduce code duplication. Signed-off-by: Wang YanQing <udknight@gmail.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2013-04-29early_printk: consolidate random copies of identical codeThomas Gleixner1-0/+1
The early console implementations are the same all over the place. Move the print function to kernel/printk and get rid of the copies. [akpm@linux-foundation.org: arch/mips/kernel/early_printk.c needs kernel.h for va_list] [paul.gortmaker@windriver.com: sh4: make the bios early console support depend on EARLY_PRINTK] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Russell King <linux@arm.linux.org.uk> Acked-by: Mike Frysinger <vapier@gentoo.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Chris Metcalf <cmetcalf@tilera.com> Cc: Richard Weinberger <richard@nod.at> Reviewed-by: Ingo Molnar <mingo@kernel.org> Tested-by: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2013-02-25Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linuxLinus Torvalds1-0/+2
Pull drm merge from Dave Airlie: "Highlights: - TI LCD controller KMS driver - TI OMAP KMS driver merged from staging - drop gma500 stub driver - the fbcon locking fixes - the vgacon dirty like zebra fix. - open firmware videomode and hdmi common code helpers - major locking rework for kms object handling - pageflip/cursor won't block on polling anymore! - fbcon helper and prime helper cleanups - i915: all over the map, haswell power well enhancements, valleyview macro horrors cleaned up, killing lots of legacy GTT code, - radeon: CS ioctl unification, deprecated UMS support, gpu reset rework, VM fixes - nouveau: reworked thermal code, external dp/tmds encoder support (anx9805), fences sleep instead of polling, - exynos: all over the driver fixes." Lovely conflict in radeon/evergreen_cs.c between commit de0babd60d8d ("drm/radeon: enforce use of radeon_get_ib_value when reading user cmd") and the new changes that modified that evergreen_dma_cs_parse() function. * 'drm-next' of git://people.freedesktop.org/~airlied/linux: (508 commits) drm/tilcdc: only build on arm drm/i915: Revert hdmi HDP pin checks drm/tegra: Add list of framebuffers to debugfs drm/tegra: Fix color expansion drm/tegra: Split DC_CMD_STATE_CONTROL register write drm/tegra: Implement page-flipping support drm/tegra: Implement VBLANK support drm/tegra: Implement .mode_set_base() drm/tegra: Add plane support drm/tegra: Remove bogus tegra_framebuffer structure drm: Add consistency check for page-flipping drm/radeon: Use generic HDMI infoframe helpers drm/tegra: Use generic HDMI infoframe helpers drm: Add EDID helper documentation drm: Add HDMI infoframe helpers video: Add generic HDMI infoframe helpers drm: Add some missing forward declarations drm: Move mode tables to drm_edid.c drm: Remove duplicate drm_mode_cea_vic() gma500: Fix n, m1 and m2 clock limits for sdvo and lvds ...
2013-02-08fb: Yet another band-aid for fixing lockdep messTakashi Iwai1-0/+1
I've still got lockdep warnings even after Alan's patch, and it seems that yet more band aids are required to paper over similar paths for unbind_con_driver() and unregister_con_driver(). After this hack, lockdep warnings are finally gone. Signed-off-by: Takashi Iwai <tiwai@suse.de> Cc: Alan Cox <alan@linux.intel.com> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: Jiri Kosina <jkosina@suse.cz> Cc: stable <stable@vger.kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-02-08fb: rework locking to fix lock ordering on takeoverAlan Cox1-0/+1
Adjust the console layer to allow a take over call where the caller already holds the locks. Make the fb layer lock in order. This is partly a band aid, the fb layer is terminally confused about the locking rules it uses for its notifiers it seems. [akpm@linux-foundation.org: remove stray non-ascii char, tidy comment] [akpm@linux-foundation.org: export do_take_over_console()] [airlied: cleanup another non-ascii char] Signed-off-by: Alan Cox <alan@linux.intel.com> Cc: Florian Tobias Schandinat <FlorianSchandinat@gmx.de> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Jiri Kosina <jkosina@suse.cz> Cc: stable <stable@vger.kernel.org> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Dave Airlie <airlied@redhat.com>
2013-01-18tty: Added a CONFIG_TTY option to allow removal of TTYJoe Millenbach1-0/+5
The option allows you to remove TTY and compile without errors. This saves space on systems that won't support TTY interfaces anyway. bloat-o-meter output is below. The bulk of this patch consists of Kconfig changes adding "depends on TTY" to various serial devices and similar drivers that require the TTY layer. Ideally, these dependencies would occur on a common intermediate symbol such as SERIO, but most drivers "select SERIO" rather than "depends on SERIO", and "select" does not respect dependencies. bloat-o-meter output comparing our previous minimal to new minimal by removing TTY. The list is filtered to not show removed entries with awk '$3 != "-"' as the list was very long. add/remove: 0/226 grow/shrink: 2/14 up/down: 6/-35356 (-35350) function old new delta chr_dev_init 166 170 +4 allow_signal 80 82 +2 static.__warned 143 142 -1 disallow_signal 63 62 -1 __set_special_pids 95 94 -1 unregister_console 126 121 -5 start_kernel 546 541 -5 register_console 593 588 -5 copy_from_user 45 40 -5 sys_setsid 128 120 -8 sys_vhangup 32 19 -13 do_exit 1543 1526 -17 bitmap_zero 60 40 -20 arch_local_irq_save 137 117 -20 release_task 674 652 -22 static.spin_unlock_irqrestore 308 260 -48 Signed-off-by: Joe Millenbach <jmillenbach@gmail.com> Reviewed-by: Jamey Sharp <jamey@minilop.net> Reviewed-by: Josh Triplett <josh@joshtriplett.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2012-10-12tty/console: fix warnings in drivers/tty/serial/kgdboc.cArnd Bergmann1-2/+8
The con_debug_leave/con_debug_enter functions are stubbed out by defining them to (0), which causes harmless build warnings. Using proper inline functions is the normal way to deal with this. Without this patch, building the ARM bcm2835_defconfig results in: drivers/tty/serial/kgdboc.c: In function 'kgdboc_pre_exp_handler': drivers/tty/serial/kgdboc.c:279:3: warning: statement with no effect [-Wunused-value] drivers/tty/serial/kgdboc.c: In function 'kgdboc_post_exp_handler': drivers/tty/serial/kgdboc.c:293:3: warning: statement with no effect [-Wunused-value] Signed-off-by: Arnd Bergmann <arnd@arndb.de> Cc: Anton Vorontsov <anton.vorontsov@linaro.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2012-01-13module_param: make bool parameters really bool (drivers & misc)Rusty Russell1-1/+1
module_param(bool) used to counter-intuitively take an int. In fddd5201 (mid-2009) we allowed bool or int/unsigned int using a messy trick. It's time to remove the int/unsigned int option. For this version it'll simply give a warning, but it'll break next kernel version. Acked-by: Mauro Carvalho Chehab <mchehab@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
2011-01-26console: rename acquire/release_console_sem() to console_lock/unlock()Torben Hohn1-3/+3
The -rt patches change the console_semaphore to console_mutex. As a result, a quite large chunk of the patches changes all acquire/release_console_sem() to acquire/release_console_mutex() This commit makes things use more neutral function names which dont make implications about the underlying lock. The only real change is the return value of console_trylock which is inverted from try_acquire_console_sem() This patch also paves the way to switching console_sem from a semaphore to a mutex. [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: make console_trylock return 1 on success, per Geert] Signed-off-by: Torben Hohn <torbenh@gmx.de> Cc: Thomas Gleixner <tglx@tglx.de> Cc: Greg KH <gregkh@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-12-16tty: add 'active' sysfs attribute to tty0 and console deviceKay Sievers1-1/+1
tty: add 'active' sysfs attribute to tty0 and console device Userspace can query the actual virtual console, and the configured console devices behind /dev/tt0 and /dev/console. The last entry in the list of devices is the active device, analog to the console= kernel command line option. The attribute supports poll(), which is raised when the virtual console is changed or /dev/console is reconfigured. Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> index 0000000..b138b66
2010-11-16console: move for_each_console to linux/console.hJiri Slaby1-0/+6
Move it out of printk.c so that we can use it all over the code. There are some potential users which will be converted to that macro in next patches. Signed-off-by: Jiri Slaby <jslaby@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-08-06console: Fix compilation regressionJason Wessel1-0/+5
A regression of building without CONFIG_HW_CONSOLE was introduced with commit b45cfba4e9005d64d419718e7ff7f7cab44c1994 (vt,console,kdb: implement atomic console enter/leave functions). ERROR: "con_debug_enter" [drivers/serial/kgdboc.ko] undefined! ERROR: "vc_cons" [drivers/serial/kgdboc.ko] undefined! ERROR: "fg_console" [drivers/serial/kgdboc.ko] undefined! ERROR: "con_debug_leave" [drivers/serial/kgdboc.ko] undefined! When there is no HW console the con_debug_enter and con_debug_leave functions should have no code. Signed-off-by: Jason Wessel <jason.wessel@windriver.com> CC: Jesse Barnes <jbarnes@virtuousgeek.org> Reported-by: Randy Dunlap <randy.dunlap@oracle.com>
2010-08-05vt,console,kdb: implement atomic console enter/leave functionsJesse Barnes1-0/+13
These functions allow the kernel debugger to save and restore the state of the system console. Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> CC: David Airlie <airlied@linux.ie> CC: Andrew Morton <akpm@linux-foundation.org>
2009-03-24vcs: hook sysfs devices into object lifetime instead of "binding"Kay Sievers1-2/+2
During bootup performance tracing I noticed many occurrences of vca* device creation and removal, leading to the usual userspace uevent processing, which are, in this case, rather pointless. A simple test showing the kernel timing (not including all the work userspace has to do), gives us these numbers: $ time for i in `seq 1000`; do echo a > /dev/tty2; done real 0m1.142s user 0m0.015s sys 0m0.540s If we move the hook for the vcs* driver core devices from the tty "binding" to the vc allocation/deallocation, which is what the vcs* devices represent, we get the following numbers: $ time for i in `seq 1000`; do echo a > /dev/tty2; done real 0m0.152s user 0m0.030s sys 0m0.072s Cc: Alan Cox <alan@lxorguk.ukuu.org.uk> Signed-off-by: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
2008-12-29DRM: add mode setting supportDave Airlie1-0/+4
Add mode setting support to the DRM layer. This is a fairly big chunk of work that allows DRM drivers to provide full output control and configuration capabilities to userspace. It was motivated by several factors: - the fb layer's APIs aren't suited for anything but simple configurations - coordination between the fb layer, DRM layer, and various userspace drivers is poor to non-existent (radeonfb excepted) - user level mode setting drivers makes displaying panic & oops messages more difficult - suspend/resume of graphics state is possible in many more configurations with kernel level support This commit just adds the core DRM part of the mode setting APIs. Driver specific commits using these new structure and APIs will follow. Co-authors: Jesse Barnes <jbarnes@virtuousgeek.org>, Jakob Bornecrantz <jakob@tungstengraphics.com> Contributors: Alan Hourihane <alanh@tungstengraphics.com>, Maarten Maathuis <madman2003@gmail.com> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Eric Anholt <eric@anholt.net> Signed-off-by: Dave Airlie <airlied@redhat.com>
2008-05-27xen: Enable console tty by default in domU if it's not a dummyMarkus Armbruster1-0/+2
Without console= arguments on the kernel command line, the first console to register becomes enabled and the preferred console (the one behind /dev/console). This is normally tty (assuming CONFIG_VT_CONSOLE is enabled, which it commonly is). This is okay as long tty is a useful console. But unless we have the PV framebuffer, and it is enabled for this domain, tty0 in domU is merely a dummy. In that case, we want the preferred console to be the Xen console hvc0, and we want it without having to fiddle with the kernel command line. Commit b8c2d3dfbc117dff26058fbac316b8acfc2cb5f7 did that for us. Since we now have the PV framebuffer, we want to enable and prefer tty again, but only when PVFB is enabled. But even then we still want to enable the Xen console as well. Problem: when tty registers, we can't yet know whether the PVFB is enabled. By the time we can know (xenstore is up), the console setup game is over. Solution: enable console tty by default, but keep hvc as the preferred console. Change the preferred console to tty when PVFB probes successfully, unless we've been given console kernel parameters. Signed-off-by: Markus Armbruster <armbru@redhat.com> Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2008-04-30Basic braille screen reader supportSamuel Thibault1-0/+4
This adds a minimalistic braille screen reader support. This is meant to be used by blind people e.g. on boot failures or when / cannot be mounted etc and thus the userland screen readers can not work. [akpm@linux-foundation.org: fix exports] Signed-off-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Cc: Jiri Kosina <jikos@jikos.cz> Cc: Dmitry Torokhov <dtor@mail.ru> Acked-by: Alan Cox <alan@redhat.com> Cc: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-18serial: turn serial console suspend a boot rather than compile time optionAndres Salomon1-5/+2
Currently, there's a CONFIG_DISABLE_CONSOLE_SUSPEND that allows one to stop the serial console from being suspended when the rest of the machine goes to sleep. This is incredibly useful for debugging power management-related things; however, having it as a compile-time option has proved to be incredibly inconvenient for us (OLPC). There are plenty of times that we want serial console to not suspend, but for the most part we'd like serial console to be suspended. This drops CONFIG_DISABLE_CONSOLE_SUSPEND, and replaces it with a kernel boot parameter (no_console_suspend). By default, the serial console will be suspended along with the rest of the system; by passing 'no_console_suspend' to the kernel during boot, serial console will remain alive during suspend. For now, this is pretty serial console specific; further fixes could be applied to make this work for things like netconsole. Signed-off-by: Andres Salomon <dilinger@debian.org> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Nigel Cunningham <nigel@suspend2.net> Cc: Russell King <rmk@arm.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-10-16vt/vgacon: Check if screen resize request comes from userspaceAntonino A. Daplas1-1/+2
Various console drivers are able to resize the screen via the con_resize() hook. This hook is also visible in userspace via the TIOCWINSZ, VT_RESIZE and VT_RESIZEX ioctl's. One particular utility, SVGATextMode, expects that con_resize() of the VGA console will always return success even if the resulting screen is not compatible with the hardware. However, this particular behavior of the VGA console, as reported in Kernel Bugzilla Bug 7513, can cause undefined behavior if the user starts with a console size larger than 80x25. To work around this problem, add an extra parameter to con_resize(). This parameter is ignored by drivers except for vgacon. If this parameter is non-zero, then the resize request came from a VT_RESIZE or VT_RESIZEX ioctl and vgacon will always return success. If this parameter is zero, vgacon will return -EINVAL if the requested size is not compatible with the hardware. The latter is the more correct behavior. With this change, SVGATextMode should still work correctly while in-kernel and stty resize calls can expect correct behavior from vgacon. Signed-off-by: Antonino Daplas <adaplas@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16Remove unnecessary includes of spinlock.h under include/linuxRobert P. J. Day1-1/+0
Remove the obviously unnecessary includes of <linux/spinlock.h> under the include/linux/ directory, and fix the couple errors that are introduced as a result of that. Signed-off-by: Robert P. J. Day <rpjday@mindspring.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-07-16serial: convert early_uart to earlycon for 8250Yinghai Lu1-0/+2
Beacuse SERIAL_PORT_DFNS is removed from include/asm-i386/serial.h and include/asm-x86_64/serial.h. the serial8250_ports need to be probed late in serial initializing stage. the console_init=>serial8250_console_init=> register_console=>serial8250_console_setup will return -ENDEV, and console ttyS0 can not be enabled at that time. need to wait till uart_add_one_port in drivers/serial/serial_core.c to call register_console to get console ttyS0. that is too late. Make early_uart to use early_param, so uart console can be used earlier. Make it to be bootconsole with CON_BOOT flag, so can use console handover feature. and it will switch to corresponding normal serial console automatically. new command line will be: console=uart8250,io,0x3f8,9600n8 console=uart8250,mmio,0xff5e0000,115200n8 or earlycon=uart8250,io,0x3f8,9600n8 earlycon=uart8250,mmio,0xff5e0000,115200n8 it will print in very early stage: Early serial console at I/O port 0x3f8 (options '9600n8') console [uart0] enabled later for console it will print: console handover: boot [uart0] -> real [ttyS0] Signed-off-by: <yinghai.lu@sun.com> Cc: Andi Kleen <ak@suse.de> Cc: Bjorn Helgaas <bjorn.helgaas@hp.com> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Gerd Hoffmann <kraxel@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08vt: add color support to the "underline" and "italic" attributesJan Engelhardt1-1/+1
Add color support to the "underline" and "italic" attributes as in OpenBSD/NetBSD-style (vt220) and xterm. Signed-off-by: Jan Engelhardt <jengelh@gmx.de> Acked-by: "Antonino A. Daplas" <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-08enlarge console.nameAndrew Morton1-3/+2
console.name[] is eight chars, but so is "earlyvga". So when we try to print console->name when using earlyvga it runs off the end of the string. Make it bigger. Diagnosed-by: Gerd Hoffmann <kraxel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-02-11[PATCH] drivers/char/vc_screen.c: proper prototypesAdrian Bunk1-0/+4
Add proper prototypes for two functions in drivers/char/vc_screen.c Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2006-10-03[PATCH] vt: proper prototypes for some console functionsAdrian Bunk1-0/+3
This patch adds proper prototypes to header files for three console init functions used on drivers/char/vt.c Signed-off-by: Adrian Bunk <bunk@stusta.de> Signed-off-by: Antonino Daplas <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-09-26[PATCH] PM: make it possible to disable console suspendingRafael J. Wysocki1-0/+5
Change suspend_console() so that it waits for all consoles to flush the remaining messages and make it possible to switch the console suspending off with the help of a Kconfig option. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> Acked-by: Pavel Machek <pavel@ucw.cz> Cc: Stefan Seyfried <seife@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26[PATCH] VT binding: Add binding/unbinding support for the VT consoleAntonino A. Daplas1-1/+3
The framebuffer console is now able to dynamically bind and unbind from the VT console layer. Due to the way the VT console layer works, the drivers themselves decide when to bind or unbind. However, it was decided that binding must be controlled, not by the drivers themselves, but by the VT console layer. With this, dynamic binding is possible for all VT console drivers, not just fbcon. Thus, the VT console layer will impose the following to all VT console drivers: - all registered VT console drivers will be entered in a private list - drivers can register themselves to the VT console layer, but they cannot decide when to bind or unbind. (Exception: To maintain backwards compatibility, take_over_console() will automatically bind the driver after registration.) - drivers can remove themselves from the list by unregistering from the VT console layer. A prerequisite for unregistration is that the driver must not be bound. The following functions are new in the vt.c: register_con_driver() - public function, this function adds the VT console driver to an internal list maintained by the VT console bind_con_driver() - private function, it binds the driver to the console take_over_console() is changed to call register_con_driver() followed by a bind_con_driver(). This is the only time drivers can decide when to bind to the VT layer. This is to maintain backwards compatibility. unbind_con_driver() - private function, it unbinds the driver from its console. The vacated consoles will be taken over by the default boot console driver. unregister_con_driver() - public function, removes the driver from the internal list maintained by the VT console. It will only succeed if the driver is currently unbound. con_is_bound() checks if the driver is currently bound or not give_up_console() is just a wrapper to unregister_con_driver(). There are also 3 additional functions meant to be called only by the tty layer for sysfs control: vt_bind() - calls bind_con_driver() vt_unbind() - calls unbind_con_driver() vt_show_drivers() - shows the list of registered drivers Most VT console drivers will continue to work as is, but might have problems when unbinding or binding which should be fixable with minimal changes. Signed-off-by: Antonino Daplas <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>