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-rw-r--r--drivers/platform/x86/apple-gmux.c113
-rw-r--r--drivers/platform/x86/dell-wmi.c5
-rw-r--r--drivers/platform/x86/intel_pmic_gpio.c4
-rw-r--r--drivers/platform/x86/thinkpad_acpi.c2
4 files changed, 118 insertions, 6 deletions
diff --git a/drivers/platform/x86/apple-gmux.c b/drivers/platform/x86/apple-gmux.c
index aa58d41ec460..f236250ac106 100644
--- a/drivers/platform/x86/apple-gmux.c
+++ b/drivers/platform/x86/apple-gmux.c
@@ -3,6 +3,7 @@
*
* Copyright (C) Canonical Ltd. <seth.forshee@canonical.com>
* Copyright (C) 2010-2012 Andreas Heider <andreas@meetr.de>
+ * Copyright (C) 2015 Lukas Wunner <lukas@wunner.de>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -26,6 +27,24 @@
#include <acpi/video.h>
#include <asm/io.h>
+/**
+ * DOC: Overview
+ *
+ * :1: http://www.latticesemi.com/en/Products/FPGAandCPLD/LatticeXP2.aspx
+ * :2: http://www.renesas.com/products/mpumcu/h8s/h8s2100/h8s2113/index.jsp
+ *
+ * gmux is a microcontroller built into the MacBook Pro to support dual GPUs:
+ * A {1}[Lattice XP2] on pre-retinas, a {2}[Renesas R4F2113] on retinas.
+ *
+ * (The MacPro6,1 2013 also has a gmux, however it is unclear why since it has
+ * dual GPUs but no built-in display.)
+ *
+ * gmux is connected to the LPC bus of the southbridge. Its I/O ports are
+ * accessed differently depending on the microcontroller: Driver functions
+ * to access a pre-retina gmux are infixed `_pio_`, those for a retina gmux
+ * are infixed `_index_`.
+ */
+
struct apple_gmux_data {
unsigned long iostart;
unsigned long iolen;
@@ -247,6 +266,20 @@ static bool gmux_is_indexed(struct apple_gmux_data *gmux_data)
return false;
}
+/**
+ * DOC: Backlight control
+ *
+ * :3: http://www.ti.com/lit/ds/symlink/lp8543.pdf
+ * :4: http://www.ti.com/lit/ds/symlink/lp8545.pdf
+ *
+ * On single GPU MacBooks, the PWM signal for the backlight is generated by
+ * the GPU. On dual GPU MacBook Pros by contrast, either GPU may be suspended
+ * to conserve energy. Hence the PWM signal needs to be generated by a separate
+ * backlight driver which is controlled by gmux. The earliest generation
+ * MBP5 2008/09 uses a {3}[TI LP8543] backlight driver. All newer models
+ * use a {4}[TI LP8545].
+ */
+
static int gmux_get_brightness(struct backlight_device *bd)
{
struct apple_gmux_data *gmux_data = bl_get_data(bd);
@@ -273,6 +306,68 @@ static const struct backlight_ops gmux_bl_ops = {
.update_status = gmux_update_status,
};
+/**
+ * DOC: Graphics mux
+ *
+ * :5: http://pimg-fpiw.uspto.gov/fdd/07/870/086/0.pdf
+ * :6: http://www.nxp.com/documents/data_sheet/CBTL06141.pdf
+ * :7: http://www.ti.com/lit/ds/symlink/hd3ss212.pdf
+ * :8: https://www.pericom.com/assets/Datasheets/PI3VDP12412.pdf
+ * :9: http://www.ti.com/lit/ds/symlink/sn74lv4066a.pdf
+ * :10: http://pdf.datasheetarchive.com/indexerfiles/Datasheets-SW16/DSASW00308511.pdf
+ * :11: http://www.ti.com/lit/ds/symlink/ts3ds10224.pdf
+ *
+ * On pre-retinas, the LVDS outputs of both GPUs feed into gmux which muxes
+ * either of them to the panel. One of the tricks gmux has up its sleeve is
+ * to lengthen the blanking interval of its output during a switch to
+ * synchronize it with the GPU switched to. This allows for a flicker-free
+ * switch that is imperceptible by the user ({5}[US 8,687,007 B2]).
+ *
+ * On retinas, muxing is no longer done by gmux itself, but by a separate
+ * chip which is controlled by gmux. The chip is triple sourced, it is
+ * either an {6}[NXP CBTL06142], {7}[TI HD3SS212] or {8}[Pericom PI3VDP12412].
+ * The panel is driven with eDP instead of LVDS since the pixel clock
+ * required for retina resolution exceeds LVDS' limits.
+ *
+ * Pre-retinas are able to switch the panel's DDC pins separately.
+ * This is handled by a {9}[TI SN74LV4066A] which is controlled by gmux.
+ * The inactive GPU can thus probe the panel's EDID without switching over
+ * the entire panel. Retinas lack this functionality as the chips used for
+ * eDP muxing are incapable of switching the AUX channel separately (see
+ * the linked data sheets, Pericom would be capable but this is unused).
+ * However the retina panel has the NO_AUX_HANDSHAKE_LINK_TRAINING bit set
+ * in its DPCD, allowing the inactive GPU to skip the AUX handshake and
+ * set up the output with link parameters pre-calibrated by the active GPU.
+ *
+ * The external DP port is only fully switchable on the first two unibody
+ * MacBook Pro generations, MBP5 2008/09 and MBP6 2010. This is done by an
+ * {6}[NXP CBTL06141] which is controlled by gmux. It's the predecessor of the
+ * eDP mux on retinas, the difference being support for 2.7 versus 5.4 Gbit/s.
+ *
+ * The following MacBook Pro generations replaced the external DP port with a
+ * combined DP/Thunderbolt port and lost the ability to switch it between GPUs,
+ * connecting it either to the discrete GPU or the Thunderbolt controller.
+ * Oddly enough, while the full port is no longer switchable, AUX and HPD
+ * are still switchable by way of an {10}[NXP CBTL03062] (on pre-retinas
+ * MBP8 2011 and MBP9 2012) or two {11}[TI TS3DS10224] (on retinas) under the
+ * control of gmux. Since the integrated GPU is missing the main link,
+ * external displays appear to it as phantoms which fail to link-train.
+ *
+ * gmux receives the HPD signal of all display connectors and sends an
+ * interrupt on hotplug. On generations which cannot switch external ports,
+ * the discrete GPU can then be woken to drive the newly connected display.
+ * The ability to switch AUX on these generations could be used to improve
+ * reliability of hotplug detection by having the integrated GPU poll the
+ * ports while the discrete GPU is asleep, but currently we do not make use
+ * of this feature.
+ *
+ * gmux' initial switch state on bootup is user configurable via the EFI
+ * variable `gpu-power-prefs-fa4ce28d-b62f-4c99-9cc3-6815686e30f9` (5th byte,
+ * 1 = IGD, 0 = DIS). Based on this setting, the EFI firmware tells gmux to
+ * switch the panel and the external DP connector and allocates a framebuffer
+ * for the selected GPU.
+ */
+
static int gmux_switchto(enum vga_switcheroo_client_id id)
{
if (id == VGA_SWITCHEROO_IGD) {
@@ -288,6 +383,14 @@ static int gmux_switchto(enum vga_switcheroo_client_id id)
return 0;
}
+/**
+ * DOC: Power control
+ *
+ * gmux is able to cut power to the discrete GPU. It automatically takes care
+ * of the correct sequence to tear down and bring up the power rails for
+ * core voltage, VRAM and PCIe.
+ */
+
static int gmux_set_discrete_state(struct apple_gmux_data *gmux_data,
enum vga_switcheroo_state state)
{
@@ -352,6 +455,16 @@ static const struct vga_switcheroo_handler gmux_handler = {
.get_client_id = gmux_get_client_id,
};
+/**
+ * DOC: Interrupt
+ *
+ * gmux is also connected to a GPIO pin of the southbridge and thereby is able
+ * to trigger an ACPI GPE. On the MBP5 2008/09 it's GPIO pin 22 of the Nvidia
+ * MCP79, on all following generations it's GPIO pin 6 of the Intel PCH.
+ * The GPE merely signals that an interrupt occurred, the actual type of event
+ * is identified by reading a gmux register.
+ */
+
static inline void gmux_disable_interrupts(struct apple_gmux_data *gmux_data)
{
gmux_write8(gmux_data, GMUX_PORT_INTERRUPT_ENABLE,
diff --git a/drivers/platform/x86/dell-wmi.c b/drivers/platform/x86/dell-wmi.c
index 5db9efbde5b9..368e193c2741 100644
--- a/drivers/platform/x86/dell-wmi.c
+++ b/drivers/platform/x86/dell-wmi.c
@@ -46,7 +46,6 @@ MODULE_LICENSE("GPL");
#define DELL_EVENT_GUID "9DBB5994-A997-11DA-B012-B622A1EF5492"
#define DELL_DESCRIPTOR_GUID "8D9DDCBC-A997-11DA-B012-B622A1EF5492"
-static int acpi_video;
static u32 dell_wmi_interface_version;
MODULE_ALIAS("wmi:"DELL_EVENT_GUID);
@@ -185,7 +184,8 @@ static void dell_wmi_process_key(int reported_key)
/* Don't report brightness notifications that will also come via ACPI */
if ((key->keycode == KEY_BRIGHTNESSUP ||
- key->keycode == KEY_BRIGHTNESSDOWN) && acpi_video)
+ key->keycode == KEY_BRIGHTNESSDOWN) &&
+ acpi_video_handles_brightness_key_presses())
return;
sparse_keymap_report_entry(dell_wmi_input_dev, key, 1, true);
@@ -525,7 +525,6 @@ static int __init dell_wmi_init(void)
return err;
dmi_walk(find_hk_type, NULL);
- acpi_video = acpi_video_get_backlight_type() != acpi_backlight_vendor;
err = dell_wmi_input_setup();
if (err)
diff --git a/drivers/platform/x86/intel_pmic_gpio.c b/drivers/platform/x86/intel_pmic_gpio.c
index 709f0afdafa8..0e73fd10ba72 100644
--- a/drivers/platform/x86/intel_pmic_gpio.c
+++ b/drivers/platform/x86/intel_pmic_gpio.c
@@ -274,11 +274,11 @@ static int platform_pmic_gpio_probe(struct platform_device *pdev)
pg->chip.base = pdata->gpio_base;
pg->chip.ngpio = NUM_GPIO;
pg->chip.can_sleep = 1;
- pg->chip.dev = dev;
+ pg->chip.parent = dev;
mutex_init(&pg->buslock);
- pg->chip.dev = dev;
+ pg->chip.parent = dev;
retval = gpiochip_add(&pg->chip);
if (retval) {
pr_err("Can not add pmic gpio chip\n");
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index a268a7abf8ab..1f0eda2cc06a 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -3489,7 +3489,7 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
/* Do not issue duplicate brightness change events to
* userspace. tpacpi_detect_brightness_capabilities() must have
* been called before this point */
- if (acpi_video_get_backlight_type() != acpi_backlight_vendor) {
+ if (acpi_video_handles_brightness_key_presses()) {
pr_info("This ThinkPad has standard ACPI backlight "
"brightness control, supported by the ACPI "
"video driver\n");