[virglrenderer-devel] Strange graphical glitches under virgl.

[Gert Wollny]

Am Freitag, den 20.07.2018, 21:47 -0700 schrieb Lepton Wu:
> Actually I tried it and it didn't work.  In my case, if I force the
> code go "use_gl" branch, it "fix" this issue. 
> The patch you said actually just patch blit_gl function. Even without
> this patch, it seems it "fix" this issue.
Sorry, for me it's early in the morning and I must have mis-read your
email, I thought that the error was in the GL path. Since both, using 
glCopyImageSubData and the GL fallback, fix this, I would assume that
there is some state leak with the blit framebuffers, unfortunately
these are really diffcult to track down, especially without a test case
 that can be automated... 

best, 
Gert 


> But I still have no idea why the regular code path have such kind of
> effects.
> On Fri, Jul 20, 2018 at 9:44 PM Gert Wollny <gert.wollny at collabora.co
> m> wrote:
> > 
> > Am Freitag, den 20.07.2018, 17:34 -0700 schrieb Lepton Wu:
> > > I think the bug is inside vrend_renderer_blit_int, I just tried
> > > to
> > > change use_gl to true inside this function and it also
> > > fixed this issue.
> > 
> > I'm thinkng about how to use the GL fallback path less, because
> > currently use_gl is used in many cases where blit would work.
> > 
> > Meanwhie you could try
> >   https://patchwork.freedesktop.org/patch/239981/
> > to see whether it fixes the issue.
> > 
> > Best,
> > Gert
> > 
> > 
> > 
> > > 
> > > So it seems use_gl==false  code path inside
> > > vrend_renderer_blit_int
> > > has some kind of bug.
> > > On Fri, Jul 20, 2018 at 4:38 PM Lepton Wu <lepton at chromium.org>
> > > wrote:
> > > > 
> > > > Thanks Gurchetan he confirmed with me that he didn't see such
> > > > kind
> > > > of
> > > > issue in his setup.
> > > > So I just upgraded everything to TOT and find out this issuse
> > > > was
> > > > gone. With bisect, I tracked down
> > > > this issue get fixed by this one:
> > > > 
> > > > https://patchwork.freedesktop.org/patch/230529/
> > > > 
> > > > So I guess does this mean there is some bug for regular memcpy
> > > > code
> > > > path?
> > > > On Fri, Jul 20, 2018 at 2:28 PM Gurchetan Singh
> > > > <gurchetansingh at chromium.org> wrote:
> > > > > 
> > > > > On Fri, Jul 20, 2018 at 2:21 PM Lepton Wu <lepton at chromium.or
> > > > > g>
> > > > > wrote:
> > > > > > 
> > > > > > Hi,
> > > > > > 
> > > > > > I have an issue which I recorded a video  to show the bug:
> > > > > > https://youtu.be/ECGDCMAOTxs
> > > > > > You can see, sometimes, there is a "wrong block" of
> > > > > > rendering.
> > > > > > It's
> > > > > > always some kind of rectangle somewhere.
> > > > > > A strange part is: I've never seen this kind of issue if I
> > > > > > am
> > > > > > running
> > > > > > 3D android games under virgl. Games always
> > > > > > running fine. But for Chrome, it sometimes come with this
> > > > > > kind
> > > > > > of
> > > > > > weird graphics.
> > > > > > 
> > > > > > So I have 2 questions:
> > > > > > 
> > > > > > 1.  What kind of guest are you using to test virgl?  I am
> > > > > > trying to
> > > > > > test some other guests to see if I can reproduce
> > > > > > same issue so I can confirm if this is something specific
> > > > > > to my
> > > > > > guest
> > > > > > (Chrome OS).
> > > > > 
> > > > > Most people use Ubuntu VMs.  It's a bit of work to setup --
> > > > > I'll
> > > > > add
> > > > > some instructions to "Virgl tips and tricks" document and
> > > > > upload
> > > > > a VM
> > > > > to the cloud.
> > > > > 
> > > > > > 2.  Do you have any rough idea that this is actually some
> > > > > > fixed
> > > > > > bug
> > > > > > upstream somewhere?  I am using TOT virglrenderer + TOT
> > > > > > qemu.
> > > > > > But my mesa (mesa-18.1_pre1) and linux kernel (4.4) in
> > > > > > guest
> > > > > > which
> > > > > > could be a little outdated.
> > > > > > 
> > > > > > Thanks for your help!
> > > > > > _______________________________________________
> > > > > > virglrenderer-devel mailing list
> > > > > > virglrenderer-devel at lists.freedesktop.org
> > > > > > https://lists.freedesktop.org/mailman/listinfo/virglrendere
> > > > > > r-de
> > > > > > vel
> > > 
> > > _______________________________________________
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> > > https://lists.freedesktop.org/mailman/listinfo/virglrenderer-deve
> > > l