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authorKeith Packard <keithp@keithp.com>2011-11-18 11:09:24 -0800
committerKeith Packard <keithp@keithp.com>2011-11-23 13:07:13 -0800
commitca88479c1c3b7b1a9f94320745f5331e1de77f80 (patch)
tree1704b84389d53be5441a805eb8e5b3ef5346f1be
parent1a2eb4604b85c5efb343da8a4dcf41288fcfca85 (diff)
drm/i915: Treat pre-gen4 backlight duty cycle value consistently
For i945 and earlier chips, the backlight frequency value had the low bit (of 16) fixed to zero. The Pineview code path handled this by just exposing the backlight range as 15 bits while other chips had the backlight range limited to 0 .. 0xfffe. This patch makes everyone take the pineview code path, providing 15 bits of backlight duty cycle range which seems more than sufficient to me. Daniel Mack reported that writing 1 to bit 0 of the duty cycle register was causing problems on his Samsung X20 notebook, even when the duty cycle value was less than the maximum backlight value. (He tried a value of 29749 with max_brightness of 29750). This patch never writes a '1' to that bit. Signed-off-by: Keith Packard <keithp@keithp.com> Reviewed-by: Takashi Iwai <tiwai@suse.de> Reported-and-tested-by: Daniel Mack <zonque@gmail.com> Cc: stable@kernel.org
-rw-r--r--drivers/gpu/drm/i915/intel_panel.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index 21f60b7d69a..04d79fd1dc9 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -178,13 +178,10 @@ u32 intel_panel_get_max_backlight(struct drm_device *dev)
if (HAS_PCH_SPLIT(dev)) {
max >>= 16;
} else {
- if (IS_PINEVIEW(dev)) {
+ if (INTEL_INFO(dev)->gen < 4)
max >>= 17;
- } else {
+ else
max >>= 16;
- if (INTEL_INFO(dev)->gen < 4)
- max &= ~1;
- }
if (is_backlight_combination_mode(dev))
max *= 0xff;
@@ -203,13 +200,12 @@ u32 intel_panel_get_backlight(struct drm_device *dev)
val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
} else {
val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
- if (IS_PINEVIEW(dev))
+ if (INTEL_INFO(dev)->gen < 4)
val >>= 1;
if (is_backlight_combination_mode(dev)) {
u8 lbpc;
- val &= ~1;
pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
val *= lbpc;
}
@@ -246,11 +242,9 @@ static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level
}
tmp = I915_READ(BLC_PWM_CTL);
- if (IS_PINEVIEW(dev)) {
- tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);
+ if (INTEL_INFO(dev)->gen < 4)
level <<= 1;
- } else
- tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
+ tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
I915_WRITE(BLC_PWM_CTL, tmp | level);
}