[BUG] drm/i915 Screen corruption introduced by a00b10c360b35d6431a94cb

[Indan Zupancic]

Huh, no idea why it didn't go to Daniel the first time, Squirrelmail never
did that before.

On Sun, February 20, 2011 03:20, Indan Zupancic wrote:
> Hi,
>
> On Sat, February 19, 2011 19:25, Daniel Vetter wrote:
>> Hi Indan,
>>
>> Please provide the usual details about your system (especially what gpu
>> this is on). Also, screenshots of what typical corruptions look like can
>> help a lot in tracking down such things.
>
> Sorry, I plainly forgot to mention that. I'm on my Thinkpad X40 with gen 2
> hardware, 855GM.
>
> I uploaded a screenshot of Firefox to:
> http://img406.imageshack.us/img406/9159/31827167.png
>
> It happens a lot when scrolling in FF on pages with images, pageup or pagedown
> don't exhibit it. Text gets corrupted as well, but in a less predictable way.
> It must be something that FF does that triggers it easily, I haven't managed
> to get it with other programs yet, though I do see some corruption in the
> window decoration too sometimes (which is Fluxbox). Scrolling horizontally
> doesn't show the same behaviour. The corruptions seems to be happening on
> the right side of a surface/window.
>
> Forcing a refresh makes it go away again (e.g. switching to another window or
> opening another window on top of it. Moving a window doesn't though). I get
> it with and without xcompmgr running.
>
> Okay, interesting titbit: For text corruption, the stripes are one pixel high
> for the default font size, no corruption for smaller sizes than the default,
> two pixel lines for 1 ctrl+ bigger than the default, 3 pixels for +2 etc.
> With bigger sizes (>=5) I get less corruption to the left of the text, but
> more in the text itself. The distance between the lines continues to increase,
> but the stripes thickness goes back to 1 pixel.
>
> Perhaps an off-by-one error somewhere?
>
>> I've created two quick patches to check a few theories, please test them
>> (both patches independently and both together). Patches attached.
>
> Tried with both applied, doesn't change anything.
>
> Greetings,
>
> Indan
>