Refactor and redesign the brightness control backend...
In order to fix bugzilla #11750...
Add a new brightness control mode: support direct NVRAM checkpointing
of the backlight level (i.e. store directly to NVRAM without the need
for UCMS calls), and use that together with the EC-based control.
Disallow UCMS+EC, thus avoiding races with the SMM firmware.
Switch the models that define HBRV (EC Brightness Value) in the DSDT
to the new mode. These are: T40-T43, R50-R52, R50e, R51e, X31-X41.
Change the default for all other IBM ThinkPads to UCMS-only. The
Lenovo models already default to UCMS-only.
Reported-by: Alexey Fisher <bug-track@xxxxxxxxxxxxxxxxx>
Signed-off-by: Henrique de Moraes Holschuh <hmh@xxxxxxxxxx>
---
Documentation/laptops/thinkpad-acpi.txt | 12 +-
drivers/platform/x86/thinkpad_acpi.c | 317 +++++++++++++++++++++----------
2 files changed, 227 insertions(+), 102 deletions(-)
diff --git a/Documentation/laptops/thinkpad-acpi.txt b/Documentation/laptops/thinkpad-acpi.txt
index 25ed43d..3d76507 100644
--- a/Documentation/laptops/thinkpad-acpi.txt
+++ b/Documentation/laptops/thinkpad-acpi.txt
@@ -1157,10 +1157,15 @@ display backlight brightness control methods have 16 levels, ranging
from 0 to 15.
There are two interfaces to the firmware for direct brightness control,
-EC and CMOS. To select which one should be used, use the
+EC and UCMS (or CMOS). To select which one should be used, use the
brightness_mode module parameter: brightness_mode=1 selects EC mode,
-brightness_mode=2 selects CMOS mode, brightness_mode=3 selects both EC
-and CMOS. The driver tries to auto-detect which interface to use.
+brightness_mode=2 selects UCMS mode, brightness_mode=3 selects EC
+mode with NVRAM backing (so that brightness changes are remembered
+across shutdown/reboot).
+
+The driver tries to select which interface to use from a table of
+defaults for each ThinkPad model. If it makes a wrong choice, please
+report this as a bug, so that we can fix it.
When display backlight brightness controls are available through the
standard ACPI interface, it is best to use it instead of this direct
@@ -1498,6 +1503,7 @@ to enable more than one output class, just add their values.
(bluetooth, WWAN, UWB...)
0x0008 HKEY event interface, hotkeys
0x0010 Fan control
+ 0x0020 Backlight brightness
There is also a kernel build option to enable more debugging
information, which may be necessary to debug driver problems.
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index 27c9480..a40b075 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -192,6 +192,7 @@ enum {
#define TPACPI_DBG_RFKILL 0x0004
#define TPACPI_DBG_HKEY 0x0008
#define TPACPI_DBG_FAN 0x0010
+#define TPACPI_DBG_BRGHT 0x0020
#define onoff(status, bit) ((status) & (1 << (bit)) ? "on" : "off")
#define enabled(status, bit) ((status) & (1 << (bit)) ? "enabled" : "disabled")
@@ -274,7 +275,6 @@ static struct {
static struct {
u16 hotkey_mask_ff:1;
- u16 bright_cmos_ec_unsync:1;
} tp_warned;
struct thinkpad_id_data {
@@ -5526,6 +5526,20 @@ static struct ibm_struct ecdump_driver_data = {
#define TPACPI_BACKLIGHT_DEV_NAME "thinkpad_screen"
+/*
+ * ThinkPads can read brightness from two places: EC HBRV (0x31), or
+ * CMOS NVRAM byte 0x5E, bits 0-3.
+ *
+ * EC HBRV (0x31) has the following layout
+ * Bit 7: unknown function
+ * Bit 6: unknown function
+ * Bit 5: Z: honour scale changes, NZ: ignore scale changes
+ * Bit 4: must be set to zero to avoid problems
+ * Bit 3-0: backlight brightness level
+ *
+ * brightness_get_raw returns status data in the HBRV layout
+ */
+
enum {
TP_EC_BACKLIGHT = 0x31,
@@ -5535,108 +5549,164 @@ enum {
TP_EC_BACKLIGHT_MAPSW = 0x20,
};
+enum tpacpi_brightness_access_mode {
+ TPACPI_BRGHT_MODE_AUTO = 0, /* Not implemented yet */
+ TPACPI_BRGHT_MODE_EC, /* EC control */
+ TPACPI_BRGHT_MODE_UCMS_STEP, /* UCMS step-based control */
+ TPACPI_BRGHT_MODE_ECNVRAM, /* EC control w/ NVRAM store */
+ TPACPI_BRGHT_MODE_MAX
+};
+
static struct backlight_device *ibm_backlight_device;
-static int brightness_mode;
+
+static enum tpacpi_brightness_access_mode brightness_mode =
+ TPACPI_BRGHT_MODE_MAX;
+
static unsigned int brightness_enable = 2; /* 2 = auto, 0 = no, 1 = yes */
static struct mutex brightness_mutex;
-/*
- * ThinkPads can read brightness from two places: EC 0x31, or
- * CMOS NVRAM byte 0x5E, bits 0-3.
- *
- * EC 0x31 has the following layout
- * Bit 7: unknown function
- * Bit 6: unknown function
- * Bit 5: Z: honour scale changes, NZ: ignore scale changes
- * Bit 4: must be set to zero to avoid problems
- * Bit 3-0: backlight brightness level
- *
- * brightness_get_raw returns status data in the EC 0x31 layout
- */
-static int brightness_get_raw(int *status)
+/* NVRAM brightness access,
+ * call with brightness_mutex held! */
+static unsigned int tpacpi_brightness_nvram_get(void)
{
- u8 lec = 0, lcmos = 0, level = 0;
+ u8 lnvram;
- if (brightness_mode & 1) {
- if (!acpi_ec_read(TP_EC_BACKLIGHT, &lec))
- return -EIO;
- level = lec & TP_EC_BACKLIGHT_LVLMSK;
- };
- if (brightness_mode & 2) {
- lcmos = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
- & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
- >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
- lcmos &= (tp_features.bright_16levels)? 0x0f : 0x07;
- level = lcmos;
- }
-
- if (brightness_mode == 3) {
- *status = lec; /* Prefer EC, CMOS is just a backing store */
- lec &= TP_EC_BACKLIGHT_LVLMSK;
- if (lec == lcmos)
- tp_warned.bright_cmos_ec_unsync = 0;
- else {
- if (!tp_warned.bright_cmos_ec_unsync) {
- printk(TPACPI_ERR
- "CMOS NVRAM (%u) and EC (%u) do not "
- "agree on display brightness level\n",
- (unsigned int) lcmos,
- (unsigned int) lec);
- tp_warned.bright_cmos_ec_unsync = 1;
- }
+ lnvram = (nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS)
+ & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
+ >> TP_NVRAM_POS_LEVEL_BRIGHTNESS;
+ lnvram &= (tp_features.bright_16levels) ? 0x0f : 0x07;
+
+ return lnvram;
+}
+
+static void tpacpi_brightness_checkpoint_nvram(void)
+{
+ u8 lec = 0;
+ u8 b_nvram;
+
+ if (brightness_mode != TPACPI_BRGHT_MODE_ECNVRAM)
+ return;
+
+ vdbg_printk(TPACPI_DBG_BRGHT,
+ "trying to checkpoint backlight level to NVRAM...\n");
+
+ if (mutex_lock_killable(&brightness_mutex) < 0)
+ return;
+
+ if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
+ goto unlock;
+ lec &= TP_EC_BACKLIGHT_LVLMSK;
+ b_nvram = nvram_read_byte(TP_NVRAM_ADDR_BRIGHTNESS);
+
+ if (lec != ((b_nvram & TP_NVRAM_MASK_LEVEL_BRIGHTNESS)
+ >> TP_NVRAM_POS_LEVEL_BRIGHTNESS)) {
+ /* NVRAM needs update */
+ b_nvram &= ~(TP_NVRAM_MASK_LEVEL_BRIGHTNESS <<
+ TP_NVRAM_POS_LEVEL_BRIGHTNESS);
+ b_nvram |= lec;
+ nvram_write_byte(b_nvram, TP_NVRAM_ADDR_BRIGHTNESS);
+ dbg_printk(TPACPI_DBG_BRGHT,
+ "updated NVRAM backlight level to %u (0x%02x)\n",
+ (unsigned int) lec, (unsigned int) b_nvram);
+ } else
+ vdbg_printk(TPACPI_DBG_BRGHT,
+ "NVRAM backlight level already is %u (0x%02x)\n",
+ (unsigned int) lec, (unsigned int) b_nvram);
+
+unlock:
+ mutex_unlock(&brightness_mutex);
+}
+
+
+/* call with brightness_mutex held! */
+static int tpacpi_brightness_get_raw(int *status)
+{
+ u8 lec = 0;
+
+ switch (brightness_mode) {
+ case TPACPI_BRGHT_MODE_UCMS_STEP:
+ *status = tpacpi_brightness_nvram_get();
+ return 0;
+ case TPACPI_BRGHT_MODE_EC:
+ case TPACPI_BRGHT_MODE_ECNVRAM:
+ if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
return -EIO;
- }
- } else {
- *status = level;
+ *status = lec;
+ return 0;
+ default:
+ return -ENXIO;
}
+}
+
+/* call with brightness_mutex held! */
+/* do NOT call with illegal backlight level value */
+static int tpacpi_brightness_set_ec(unsigned int value)
+{
+ u8 lec = 0;
+
+ if (unlikely(!acpi_ec_read(TP_EC_BACKLIGHT, &lec)))
+ return -EIO;
+
+ if (unlikely(!acpi_ec_write(TP_EC_BACKLIGHT,
+ (lec & TP_EC_BACKLIGHT_CMDMSK) |
+ (value & TP_EC_BACKLIGHT_LVLMSK))))
+ return -EIO;
+
+ return 0;
+}
+
+/* call with brightness_mutex held! */
+static int tpacpi_brightness_set_ucmsstep(unsigned int value)
+{
+ int cmos_cmd, inc;
+ unsigned int current_value, i;
+
+ current_value = tpacpi_brightness_nvram_get();
+
+ if (value == current_value)
+ return 0;
+
+ cmos_cmd = (value > current_value) ?
+ TP_CMOS_BRIGHTNESS_UP :
+ TP_CMOS_BRIGHTNESS_DOWN;
+ inc = (value > current_value) ? 1 : -1;
+
+ for (i = current_value; i != value; i += inc)
+ if (issue_thinkpad_cmos_command(cmos_cmd))
+ return -EIO;
return 0;
}
/* May return EINTR which can always be mapped to ERESTARTSYS */
-static int brightness_set(int value)
+static int brightness_set(unsigned int value)
{
- int cmos_cmd, inc, i, res;
- int current_value;
- int command_bits;
+ int res;
if (value > ((tp_features.bright_16levels)? 15 : 7) ||
value < 0)
return -EINVAL;
+ vdbg_printk(TPACPI_DBG_BRGHT,
+ "set backlight level to %d\n", value);
+
res = mutex_lock_killable(&brightness_mutex);
if (res < 0)
return res;
- res = brightness_get_raw(¤t_value);
- if (res < 0)
- goto errout;
-
- command_bits = current_value & TP_EC_BACKLIGHT_CMDMSK;
- current_value &= TP_EC_BACKLIGHT_LVLMSK;
-
- cmos_cmd = value > current_value ?
- TP_CMOS_BRIGHTNESS_UP :
- TP_CMOS_BRIGHTNESS_DOWN;
- inc = (value > current_value)? 1 : -1;
-
- res = 0;
- for (i = current_value; i != value; i += inc) {
- if ((brightness_mode & 2) &&
- issue_thinkpad_cmos_command(cmos_cmd)) {
- res = -EIO;
- goto errout;
- }
- if ((brightness_mode & 1) &&
- !acpi_ec_write(TP_EC_BACKLIGHT,
- (i + inc) | command_bits)) {
- res = -EIO;
- goto errout;;
- }
+ switch (brightness_mode) {
+ case TPACPI_BRGHT_MODE_EC:
+ case TPACPI_BRGHT_MODE_ECNVRAM:
+ res = tpacpi_brightness_set_ec(value);
+ break;
+ case TPACPI_BRGHT_MODE_UCMS_STEP:
+ res = tpacpi_brightness_set_ucmsstep(value);
+ break;
+ default:
+ res = -ENXIO;
}
-errout:
mutex_unlock(&brightness_mutex);
return res;
}
@@ -5645,21 +5715,34 @@ errout:
static int brightness_update_status(struct backlight_device *bd)
{
- /* it is the backlight class's job (caller) to handle
- * EINTR and other errors properly */
- return brightness_set(
+ unsigned int level =
(bd->props.fb_blank == FB_BLANK_UNBLANK &&
bd->props.power == FB_BLANK_UNBLANK) ?
- bd->props.brightness : 0);
+ bd->props.brightness : 0;
+
+ dbg_printk(TPACPI_DBG_BRGHT,
+ "backlight: attempt to set level to %d\n",
+ level);
+
+ /* it is the backlight class's job (caller) to handle
+ * EINTR and other errors properly */
+ return brightness_set(level);
}
static int brightness_get(struct backlight_device *bd)
{
int status, res;
- res = brightness_get_raw(&status);
+ res = mutex_lock_killable(&brightness_mutex);
if (res < 0)
- return 0; /* FIXME: teach backlight about error handling */
+ return 0;
+
+ res = tpacpi_brightness_get_raw(&status);
+
+ mutex_unlock(&brightness_mutex);
+
+ if (res < 0)
+ return 0;
return status & TP_EC_BACKLIGHT_LVLMSK;
}
@@ -5709,7 +5792,7 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
}
if (!brightness_enable) {
- dbg_printk(TPACPI_DBG_INIT,
+ dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
"brightness support disabled by "
"module parameter\n");
return 1;
@@ -5724,20 +5807,38 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
if (b == 16)
tp_features.bright_16levels = 1;
- if (!brightness_mode) {
- if (thinkpad_id.vendor == PCI_VENDOR_ID_LENOVO)
- brightness_mode = 2;
- else
- brightness_mode = 3;
+ /*
+ * Check for module parameter bogosity, note that we
+ * init brightness_mode to TPACPI_BRGHT_MODE_MAX in order to be
+ * able to detect "unspecified"
+ */
+ if (brightness_mode > TPACPI_BRGHT_MODE_MAX)
+ return -EINVAL;
- dbg_printk(TPACPI_DBG_INIT, "selected brightness_mode=%d\n",
- brightness_mode);
- }
+ /* TPACPI_BRGHT_MODE_AUTO not implemented yet, just use default */
+ if (brightness_mode == TPACPI_BRGHT_MODE_AUTO ||
+ brightness_mode == TPACPI_BRGHT_MODE_MAX) {
+ if (thinkpad_id.vendor == PCI_VENDOR_ID_IBM) {
+ /*
+ * IBM models that define HBRV probably have
+ * EC-based backlight level control
+ */
+ if (acpi_evalf(ec_handle, NULL, "HBRV", "qd"))
+ /* T40-T43, R50-R52, R50e, R51e, X31-X41 */
+ brightness_mode = TPACPI_BRGHT_MODE_ECNVRAM;
+ else
+ /* all other IBM ThinkPads */
+ brightness_mode = TPACPI_BRGHT_MODE_UCMS_STEP;
+ } else
+ /* All Lenovo ThinkPads */
+ brightness_mode = TPACPI_BRGHT_MODE_UCMS_STEP;
- if (brightness_mode > 3)
- return -EINVAL;
+ dbg_printk(TPACPI_DBG_BRGHT,
+ "selected brightness_mode=%d\n",
+ brightness_mode);
+ }
- if (brightness_get_raw(&b) < 0)
+ if (tpacpi_brightness_get_raw(&b) < 0)
return 1;
if (tp_features.bright_16levels)
@@ -5751,7 +5852,8 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
printk(TPACPI_ERR "Could not register backlight device\n");
return PTR_ERR(ibm_backlight_device);
}
- vdbg_printk(TPACPI_DBG_INIT, "brightness is supported\n");
+ vdbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_BRGHT,
+ "brightness is supported\n");
ibm_backlight_device->props.max_brightness =
(tp_features.bright_16levels)? 15 : 7;
@@ -5761,13 +5863,25 @@ static int __init brightness_init(struct ibm_init_struct *iibm)
return 0;
}
+static void brightness_suspend(pm_message_t state)
+{
+ tpacpi_brightness_checkpoint_nvram();
+}
+
+static void brightness_shutdown(void)
+{
+ tpacpi_brightness_checkpoint_nvram();
+}
+
static void brightness_exit(void)
{
if (ibm_backlight_device) {
- vdbg_printk(TPACPI_DBG_EXIT,
+ vdbg_printk(TPACPI_DBG_EXIT | TPACPI_DBG_BRGHT,
"calling backlight_device_unregister()\n");
backlight_device_unregister(ibm_backlight_device);
}
+
+ tpacpi_brightness_checkpoint_nvram();
}
static int brightness_read(char *p)
@@ -5814,6 +5928,9 @@ static int brightness_write(char *buf)
return -EINVAL;
}
+ tpacpi_disclose_usertask("procfs brightness",
+ "set level to %d\n", level);
+
/*
* Now we know what the final level should be, so we try to set it.
* Doing it this way makes the syscall restartable in case of EINTR
@@ -5827,6 +5944,8 @@ static struct ibm_struct brightness_driver_data = {
.read = brightness_read,
.write = brightness_write,
.exit = brightness_exit,
+ .suspend = brightness_suspend,
+ .shutdown = brightness_shutdown,
};
/*************************************************************************
@@ -7464,10 +7583,10 @@ module_param_named(fan_control, fan_control_allowed, bool, 0);
MODULE_PARM_DESC(fan_control,
"Enables setting fan parameters features when true");
-module_param_named(brightness_mode, brightness_mode, int, 0);
+module_param_named(brightness_mode, brightness_mode, uint, 0);
MODULE_PARM_DESC(brightness_mode,
"Selects brightness control strategy: "
- "0=auto, 1=EC, 2=CMOS, 3=both");
+ "0=auto, 1=EC, 2=UCMS, 3=EC+NVRAM");
module_param(brightness_enable, uint, 0);
MODULE_PARM_DESC(brightness_enable,
--
1.6.2.1
--
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