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<b><a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED --- - [sna gen4] corrupt rendering (and flickering on redraw)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=55500#c85">Comment # 85</a>
on <a class="bz_bug_link
bz_status_ASSIGNED "
title="ASSIGNED --- - [sna gen4] corrupt rendering (and flickering on redraw)"
href="https://bugs.freedesktop.org/show_bug.cgi?id=55500">bug 55500</a>
from <span class="vcard"><a class="email" href="mailto:zdenek.kabelac@gmail.com" title="Zdenek Kabelac <zdenek.kabelac@gmail.com>"> <span class="fn">Zdenek Kabelac</span></a>
</span></b>
<pre>(In reply to <a href="show_bug.cgi?id=55500#c84">comment #84</a>)
<span class="quote">> Yes, that is characteristic of this bug. The internal vertex/texture
> coordinates that are being passed along the GPU pipeline become corrupt (it
> looks like we overflow a small ring buffer). The only effective approach</span >
If it would be plain 'overflow' - than I'd be seeing this kind of corruption
always right after X starts.
But it seems like i.e. Firefox must be used for certain period of time,
to make these corruptions visible.
Surely I'm not not an expert on GPU programming - but maybe when the physical
memory gets fragmented enough after some usage there are some 'cached bo'
objects - maybe their usage is not fully synchronized?
Also the effect could also disappear (I've not yet noticed any particular way
for that) - so then Firefox scroll even the very same pages and there
is no problem (i.e. now I run still the same session - and I do not get any
visible problem)
<span class="quote">> I've found so far has been to keep the number of rectangles inside the GPU
> pipeline below a magic value - but that is quite tricky here, and the</span >
Well why the number would sometimes work for ours without a single visible
problem, and suddenly start to show them again?
My impression here is, when this problem is visible,
it looks like operations is working with 'wrong' parameters
(i.e. sometimes I see the image stretched, inverted, zoomed)
Maybe parameters have only some bits mangled - not fully synchronized memory
from CPU for GPU??</pre>
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