From: Daniel Vetter <daniel@ffwll.ch>
To: Takashi Iwai <tiwai@suse.de>
Cc: Jani Nikula <jani.nikula@intel.com>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Intel Graphics Development <intel-gfx@lists.freedesktop.org>
Subject: Re: [PATCH] Revert "drm/i915: write backlight harder"
Date: Sat, 23 Mar 2013 12:36:24 +0100 [thread overview]
Message-ID: <20130323113624.GX9021@phenom.ffwll.local> (raw)
In-Reply-To: <s5hehf7a2zd.wl%tiwai@suse.de>
On Fri, Mar 22, 2013 at 04:06:14PM +0100, Takashi Iwai wrote:
> At Fri, 22 Mar 2013 15:44:46 +0100,
> Daniel Vetter wrote:
> >
> > This reverts commit cf0a6584aa6d382f802f2c3cacac23ccbccde0cd.
> >
> > Turns out that cargo-culting breaks systems. Note that we can't revert
> > further, since
> >
> > commit 770c12312ad617172b1a65b911d3e6564fc5aca8
> > Author: Takashi Iwai <tiwai@suse.de>
> > Date: Sat Aug 11 08:56:42 2012 +0200
> >
> > drm/i915: Fix blank panel at reopening lid
> >
> > fixed a regression in 3.6-rc kernels for which we've never figured out
> > the exact root cause. But some further inspection of the backlight
> > code reveals that it's seriously lacking locking. And especially the
> > asle backlight update is know to get fired (through some smm magic)
> > when writing specific backlight control registers. So the possibility
> > of suffering from races is rather real.
> >
> > Until those races are fixed I don't think it makes sense to try
> > further hacks. Which sucks a bit, but sometimes that's how it is :(
> >
> > References: http://www.mail-archive.com/intel-gfx@lists.freedesktop.org/msg18788.html
> > Cc: Jani Nikula <jani.nikula@intel.com>
> > Cc: Takashi Iwai <tiwai@suse.de>
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
>
> Feel free to add my tested-by tags to all three.
>
> Tested-by: Takashi Iwai <tiwai@suse.de>
Picked up for -fixes with the additional kernel bz link for #47941 added.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
next prev parent reply other threads:[~2013-03-23 11:33 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-22 9:53 [PATCH 1/3] Revert "drm/i915: dynamic Haswell display power well support" Daniel Vetter
2013-03-22 9:53 ` [PATCH 2/3] Revert "drm/i915: set TRANSCODER_EDP even earlier" Daniel Vetter
2013-03-22 12:30 ` Paulo Zanoni
2013-03-22 13:59 ` Daniel Vetter
2013-03-22 13:43 ` Daniel Vetter
2013-03-22 9:53 ` [PATCH 3/3] drm/i915: Revert backlight cargo-culting Daniel Vetter
2013-03-22 10:00 ` Takashi Iwai
2013-03-22 10:13 ` Daniel Vetter
2013-03-22 10:22 ` Daniel Vetter
2013-03-22 10:42 ` Takashi Iwai
2013-03-22 11:22 ` Daniel Vetter
2013-03-22 11:34 ` Takashi Iwai
2013-03-22 14:01 ` Daniel Vetter
2013-03-22 14:44 ` [PATCH] Revert "drm/i915: write backlight harder" Daniel Vetter
2013-03-22 15:06 ` Takashi Iwai
2013-03-23 11:36 ` Daniel Vetter [this message]
2013-03-22 14:45 ` [PATCH 1/7] drm/i915: don't disable the power well yet Paulo Zanoni
2013-03-22 15:22 ` Daniel Vetter
2013-03-22 17:07 ` Paulo Zanoni
2013-03-23 11:34 ` Daniel Vetter
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