drm/i915: fix opregion backlight chip detect and range
BLC_PWM_CTL2 is for 965+ only, so add device model check for
legacy backlight control.
For native backlight control, it maps the backlight value (0~255)
in opregion ASLE[BCLP] to backlight duty cycle (0~max_backlight)
and set into control register.
It also add support for IGD device, which follows opregion spec.
Signed-off-by: Li Peng <peng.li@intel.com>
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
diff --git a/drivers/gpu/drm/i915/i915_opregion.c b/drivers/gpu/drm/i915/i915_opregion.c
index e4b4e88..2d51935 100644
--- a/drivers/gpu/drm/i915/i915_opregion.c
+++ b/drivers/gpu/drm/i915/i915_opregion.c
@@ -148,6 +148,7 @@
struct drm_i915_private *dev_priv = dev->dev_private;
struct opregion_asle *asle = dev_priv->opregion.asle;
u32 blc_pwm_ctl, blc_pwm_ctl2;
+ u32 max_backlight, level, shift;
if (!(bclp & ASLE_BCLP_VALID))
return ASLE_BACKLIGHT_FAIL;
@@ -157,14 +158,25 @@
return ASLE_BACKLIGHT_FAIL;
blc_pwm_ctl = I915_READ(BLC_PWM_CTL);
- blc_pwm_ctl &= ~BACKLIGHT_DUTY_CYCLE_MASK;
blc_pwm_ctl2 = I915_READ(BLC_PWM_CTL2);
- if (blc_pwm_ctl2 & BLM_COMBINATION_MODE)
+ if (IS_I965G(dev) && (blc_pwm_ctl2 & BLM_COMBINATION_MODE))
pci_write_config_dword(dev->pdev, PCI_LBPC, bclp);
- else
- I915_WRITE(BLC_PWM_CTL, blc_pwm_ctl | ((bclp * 0x101)-1));
-
+ else {
+ if (IS_IGD(dev)) {
+ blc_pwm_ctl &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);
+ max_backlight = (blc_pwm_ctl & BACKLIGHT_MODULATION_FREQ_MASK) >>
+ BACKLIGHT_MODULATION_FREQ_SHIFT;
+ shift = BACKLIGHT_DUTY_CYCLE_SHIFT + 1;
+ } else {
+ blc_pwm_ctl &= ~BACKLIGHT_DUTY_CYCLE_MASK;
+ max_backlight = ((blc_pwm_ctl & BACKLIGHT_MODULATION_FREQ_MASK) >>
+ BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
+ shift = BACKLIGHT_DUTY_CYCLE_SHIFT;
+ }
+ level = (bclp * max_backlight) / 255;
+ I915_WRITE(BLC_PWM_CTL, blc_pwm_ctl | (level << shift));
+ }
asle->cblv = (bclp*0x64)/0xff | ASLE_CBLV_VALID;
return 0;