Re: i835GM flicker on panning

[Daniel Vetter]

Hm, that sounds a bit more like the ddx is having fun with rendering.
Have you tried switching the backed from to either SNA or UXA? Also
adding relevant mailing lists ...
-Daniel

On Sun, Sep 22, 2013 at 7:06 PM, Thomas Richter <thor@xxxxxxxxxxxxxxxxx> wrote:
> Hi folks, hi Daniel,
>
> there is still an issue with flicker on panning with the 835GM chipset. As
> already explained, the flicker only appears if the panning position
> satisfies certain alignment constraints, in specific. As long as the plane
> pointer is aligned to 64 byte boundaries, everything works correctly.
>
> I tried now to add a parameter to the kernel to adjust the watermark level
> of the chipset and see whether this makes any difference with regards to the
> flicker. However, it does not. It seems that the trouble is not there.
>
> However, I noticed something interesting: If I use a non-native mode of the
> display, i.e. enable the scaling feature of the DVO, everything works, and
> no flicker ever appears. However, in these situations the resolution is also
> lower than that of the native display, and hence the issue may also be
> related to the PLL clock.
>
> I also noticed that if I invert the display, i.e. use the rotation feature,
> even in the native resolution, nothing flickers, though panning is rather
> slow.
>
> Does this somehow ring a bell? Can I somehow force the driver to use the
> same logic for the regular display as for the inverted display to avoid the
> flicker?
>
> Any help would be appreciated.
>
> Greetings,
>         Thomas
>



-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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