At Mon, 14 Nov 2011 13:03:46 +0100, Daniel Mack wrote:
On 11/14/2011 11:39 AM, Takashi Iwai wrote:
[Added Chris to Cc]
At Sun, 13 Nov 2011 17:24:09 +0100, Daniel Mack wrote:
Hi Takashi,
On 11/10/2011 04:39 PM, Takashi Iwai wrote:
At Thu, 10 Nov 2011 16:11:29 +0100, Daniel Mack wrote:
On 11/08/2011 01:57 AM, Daniel Mack wrote:
Didn't get any response yet, hence copying LKML for a broader audience.
Nobody, really?
This is a rather annoying regression, as touching the brightness keys appearantly switches off the whole machine. I'm sure this is trivial to fix, I just don't have the insight of this driver and the chipset.
I vaguely remember that the bit 0 is invalid on some old chips. Maybe 915GM is one of them, as it's gen3? If so, the patch like below may work.
Thank you for looking into this.
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c index 499d4c0..be952d1 100644 --- a/drivers/gpu/drm/i915/intel_panel.c +++ b/drivers/gpu/drm/i915/intel_panel.c @@ -249,8 +249,11 @@ static void intel_panel_actually_set_backlight(struct drm_device *dev, u32 level if (IS_PINEVIEW(dev)) { tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1); level <<= 1;
- } else
- } else { tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
if (INTEL_INFO(dev)->gen < 4)tmp &= ~1;- } I915_WRITE(BLC_PWM_CTL, tmp | level);
}
This seems to be the right intention, but the value you want to modify under this condition is 'level', not 'tmp'.
Ah, of course. Sorry for that.
With this amendment of your patch, things work perfectly fine here.
OK, then perhaps a better fix is to change the check to be equivalent with pineview, as you mentioned in the original post. The handling of bit 0 for old chips was lost during the refactoring of backlight code since 2.6.37.
Does the patch below work for you?
Will test, but I only have occasional access to the machine, so this will have to wait for some days.
It's an old bug over a year, so no need to hurry.
Takashi