diff options
| -rw-r--r-- | Documentation/laptops/thinkpad-acpi.txt | 11 | ||||
| -rw-r--r-- | drivers/platform/x86/Kconfig | 24 | ||||
| -rw-r--r-- | drivers/platform/x86/thinkpad_acpi.c | 76 |
3 files changed, 91 insertions, 20 deletions
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt index de6f14c79070..bce1d959b703 100644 --- a/Documentation/laptops/thinkpad-acpi.txt +++ b/Documentation/laptops/thinkpad-acpi.txt @@ -901,6 +901,17 @@ some older ThinkPad models, it is possible to query the status of the LED indicators as well. Newer ThinkPads cannot query the real status of the LED indicators. +Because misuse of the LEDs could induce an unaware user to perform +dangerous actions (like undocking or ejecting a bay device while the +buses are still active), or mask an important alarm (such as a nearly +empty battery, or a broken battery), access to most LEDs is +restricted. + +Unrestricted access to all LEDs requires that thinkpad-acpi be +compiled with the CONFIG_THINKPAD_ACPI_UNSAFE_LEDS option enabled. +Distributions must never enable this option. Individual users that +are aware of the consequences are welcome to enabling it. + procfs notes: The available commands are: diff --git a/drivers/platform/x86/Kconfig b/drivers/platform/x86/Kconfig index 3608081bc3e0..d45c6ab729f8 100644 --- a/drivers/platform/x86/Kconfig +++ b/drivers/platform/x86/Kconfig @@ -226,6 +226,30 @@ config THINKPAD_ACPI_DEBUG If you are not sure, say N here. +config THINKPAD_ACPI_UNSAFE_LEDS + bool "Allow control of important LEDs (unsafe)" + depends on THINKPAD_ACPI + default n + ---help--- + Overriding LED state on ThinkPads can mask important + firmware alerts (like critical battery condition), or misled + the user into damaging the hardware (undocking or ejecting + the bay while buses are still active), etc. + + LED control on the ThinkPad is write-only (with very few + exceptions on very ancient models), which makes it + impossible to know beforehand if important information will + be lost when one changes LED state. + + Users that know what they are doing can enable this option + and the driver will allow control of every LED, including + the ones on the dock stations. + + Never enable this option on a distribution kernel. + + Say N here, unless you are building a kernel for your own + use, and need to control the important firmware LEDs. + config THINKPAD_ACPI_DOCK bool "Legacy Docking Station Support" depends on THINKPAD_ACPI diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index f003fb7c79ca..38c34c79ff35 100644 --- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -4657,6 +4657,16 @@ static const char * const tpacpi_led_names[TPACPI_LED_NUMLEDS] = { "tpacpi::unknown_led", "tpacpi::standby", }; +#define TPACPI_SAFE_LEDS 0x0081U + +static inline bool tpacpi_is_led_restricted(const unsigned int led) +{ +#ifdef CONFIG_THINKPAD_ACPI_UNSAFE_LEDS + return false; +#else + return (TPACPI_SAFE_LEDS & (1 << led)) == 0; +#endif +} static int led_get_status(const unsigned int led) { @@ -4694,16 +4704,20 @@ static int led_set_status(const unsigned int led, switch (led_supported) { case TPACPI_LED_570: /* 570 */ - if (led > 7) + if (unlikely(led > 7)) return -EINVAL; + if (unlikely(tpacpi_is_led_restricted(led))) + return -EPERM; if (!acpi_evalf(led_handle, NULL, NULL, "vdd", (1 << led), led_sled_arg1[ledstatus])) rc = -EIO; break; case TPACPI_LED_OLD: /* 600e/x, 770e, 770x, A21e, A2xm/p, T20-22, X20 */ - if (led > 7) + if (unlikely(led > 7)) return -EINVAL; + if (unlikely(tpacpi_is_led_restricted(led))) + return -EPERM; rc = ec_write(TPACPI_LED_EC_HLMS, (1 << led)); if (rc >= 0) rc = ec_write(TPACPI_LED_EC_HLBL, @@ -4714,6 +4728,10 @@ static int led_set_status(const unsigned int led, break; case TPACPI_LED_NEW: /* all others */ + if (unlikely(led >= TPACPI_LED_NUMLEDS)) + return -EINVAL; + if (unlikely(tpacpi_is_led_restricted(led))) + return -EPERM; if (!acpi_evalf(led_handle, NULL, NULL, "vdd", led, led_led_arg1[ledstatus])) rc = -EIO; @@ -4806,6 +4824,30 @@ static void led_exit(void) kfree(tpacpi_leds); } +static int __init tpacpi_init_led(unsigned int led) +{ + int rc; + + tpacpi_leds[led].led = led; + + tpacpi_leds[led].led_classdev.brightness_set = &led_sysfs_set; + tpacpi_leds[led].led_classdev.blink_set = &led_sysfs_blink_set; + if (led_supported == TPACPI_LED_570) + tpacpi_leds[led].led_classdev.brightness_get = + &led_sysfs_get; + + tpacpi_leds[led].led_classdev.name = tpacpi_led_names[led]; + + INIT_WORK(&tpacpi_leds[led].work, led_set_status_worker); + + rc = led_classdev_register(&tpacpi_pdev->dev, + &tpacpi_leds[led].led_classdev); + if (rc < 0) + tpacpi_leds[led].led_classdev.name = NULL; + + return rc; +} + static int __init led_init(struct ibm_init_struct *iibm) { unsigned int i; @@ -4839,27 +4881,21 @@ static int __init led_init(struct ibm_init_struct *iibm) } for (i = 0; i < TPACPI_LED_NUMLEDS; i++) { - tpacpi_leds[i].led = i; - - tpacpi_leds[i].led_classdev.brightness_set = &led_sysfs_set; - tpacpi_leds[i].led_classdev.blink_set = &led_sysfs_blink_set; - if (led_supported == TPACPI_LED_570) - tpacpi_leds[i].led_classdev.brightness_get = - &led_sysfs_get; - - tpacpi_leds[i].led_classdev.name = tpacpi_led_names[i]; - - INIT_WORK(&tpacpi_leds[i].work, led_set_status_worker); - - rc = led_classdev_register(&tpacpi_pdev->dev, - &tpacpi_leds[i].led_classdev); - if (rc < 0) { - tpacpi_leds[i].led_classdev.name = NULL; - led_exit(); - return rc; + if (!tpacpi_is_led_restricted(i)) { + rc = tpacpi_init_led(i); + if (rc < 0) { + led_exit(); + return rc; + } } } +#ifdef CONFIG_THINKPAD_ACPI_UNSAFE_LEDS + if (led_supported != TPACPI_LED_NONE) + printk(TPACPI_NOTICE + "warning: userspace override of important " + "firmware LEDs is enabled\n"); +#endif return (led_supported != TPACPI_LED_NONE)? 0 : 1; } |