Bug#597358: xserver-xorg-video-radeon: Screen brightness flickers when KMS is enabled
On 07.09.2011 13:36, Jonathan Nieder wrote:
> Hi,
>
> Aaron Small wrote[1]:
>
>> When KMS is enabled, the screen is mostly correct all the time, but the
>> brightness for either the entire screen, or one horizontal line
>> flickers, maybe two to three times per second. Sometimes the change in
>> brightness is just noticeable, and sometimes it is strong enough to look
>> like a horizontal line the full width of the display becomes white.
>
> Alex Deucher wrote:
>
>> Can you try this set of kernel patches?
> [...]
>> Yes, it will affect all radeons, but in practice it's should really
>> only change things on avivo hw (r5xx+) due to the limited number of
>> post dividers on pre-avivo hardware. It's the same algo that was used
>> originally on all radeons, before I added the newer algo; the only
>> tweak is that we prefer higher post dividers rather than lower ones.
>> In practice, it seems the older one works better. I've tested them on
>> a variety of monitors on all my radeon cards (r1xx-evergreen
>> families). Additionally these patches have fixed several bugs where
>> the newer algo did not work properly.
>
> Aaron Small wrote (after testing on top of "master"):
>
>> Yes, these patches fix the problem.
>
> Stefan, do these three patches look like reasonable candidates for the
> linux-2.6.32.y-drm33.z tree? They are straightforward backports of
> patches from mainline (so please feel free to skip the patches and
> cherry-pick them for yourself :)). This series doesn't include
> "drm/radeon/kms: remove new pll algo" because in 2.6.33 the newer algo
> hadn't been introduced yet.
>
> Aaron, if you get a chance to test this series on top of the squeeze
> kernel, that would be interesting of course. :)
>
> Alex Deucher (2):
> drm/radeon/kms: prefer high post dividers in legacy pll algo
> drm/radeon/kms: remove some pll algo flags
>
> Dan Carpenter (1):
> drm: radeon: fix sign bug
>
> drivers/gpu/drm/radeon/atombios_crtc.c | 14 +---------
> drivers/gpu/drm/radeon/radeon_display.c | 36 ++++++---------------------
> drivers/gpu/drm/radeon/radeon_legacy_crtc.c | 5 ---
> drivers/gpu/drm/radeon/radeon_mode.h | 12 ++------
> 4 files changed, 12 insertions(+), 55 deletions(-)
>
> Looking forward to your thoughts,
> Jonathan
>
> [1] http://bugs.debian.org/597358
Hi Jonathan,
only having looked at them very briefly, the first two look quite reasonable.
The last one "remove some pll algo flags" I would want to look at more closely.
Just as it is at least bigger from the amount of modifications. Other question
would be whether it is required or just cleaning up things.
So in general,looks ok. Just need a bit time to look closer into it. And I am
travelling at the moment which slows things a bit.
-Stefan
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