Re: [PATCH] properly enable the blc controller on the right pipe

From: Carsten Emde <C.Emde@osadl.org>
To: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>,
	Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] properly enable the blc controller on the right pipe
Date: Thu, 26 Jul 2012 00:35:22 +0200	[thread overview]
Message-ID: <501074AA.1070905@osadl.org> (raw)
In-Reply-To: <500E4F12.9040906@osadl.org>

On 07/24/2012 09:30 AM, Carsten Emde wrote:
> On 07/20/2012 10:10 AM, Daniel Vetter wrote:
>> On Fri, Jul 20, 2012 at 12:51:41AM +0200, Carsten Emde wrote:
>>> On 07/19/2012 04:40 PM, Daniel Vetter wrote:
>>>> Well, the backlight-confusion branch had a bug and outright disabled
>>>> the intel backlight :( drm-intel-next-queued should have fixes for all
>>>> the backlight goofus I've accidentally created, so testing feedback on
>>>> that branch would be highly appreciated.
>>> This branch is now broken again. The original drm-intel-next-queued
>>> branch works well (it still has the quirk), but after I reverted the
>>> Acer quirk, the screen remains dark.
>>>
>>> I double-checked it and used exactly the same patch to revert the
>>> quirk in the two trees: The backlight-confusion branch works, and
>>> the drm-intel-next-queued branch does not.
>>>
>>> I then used drivers/gpu/drm/i915/intel_panel.c from
>>> backlight-confusion in drm-intel-next-queued and - it worked again.
>>> When testing the two differences separately it turned out this patch
>>> did the magic:
>>
>> Yeah, I guess your system only worked whith the old code because it
>> accidentally disabled the entire backlight stuff. Now that that doesn't
>> happen any more, it's as broken as ever.
>>
>> I'll look into creating another patch, afaict from digging through git
>> history, this backlight combination mode is totally bogus. But if we kill
>> it, a few machines will resume with dimmed backlight, because we don't
>> restore the lbpc register properly.
> After all that hassle and bearing in mind that we found only two
> notebooks so far, Acer Aspire 5732Z and 5734Z, that suffer from this
> backlight inversion problem, shouldn't we simply return to the quirk
> solution? I would quickly add the data of the other Acer to the
> backlight quirks, send a rebased patch, and we are all set.
These are the data of the other Acer Aspire that needs backlight inversion.

  Index: linux-git/drivers/gpu/drm/i915/intel_display.c
===================================================================

--- linux-git.orig/drivers/gpu/drm/i915/intel_display.c
+++ linux-git/drivers/gpu/drm/i915/intel_display.c
@@ -6877,7 +6877,8 @@ static struct intel_quirk intel_quirks[]
  	/* Sony Vaio Y cannot use SSC on LVDS */
  	{ 0x0046, 0x104d, 0x9076, quirk_ssc_force_disable },

-	/* Acer Aspire 5734Z must invert backlight brightness */
+	/* Acer Aspire 5732Z and 5734Z must invert backlight brightness */
+	{ 0x2a42, 0x1025, 0x0212, quirk_invert_brightness },
  	{ 0x2a42, 0x1025, 0x0459, quirk_invert_brightness },
  };

Do you wish me to submit this as a regular patch?

	-Carsten.
