[virglrenderer-devel] Strange graphical glitches under virgl.

[Lepton Wu]

Actually I have a question for glCopyImageSubData,  from the spec:

https://www.khronos.org/registry/OpenGL-Refpages/gl4/html/glCopyImageSubData.xhtml

It said:  "srcY The Y coordinate of the top edge of the source region to copy."

But in the regular path, my feeling is that we treat the that
src.box.y as  the lower bounder of the rectangle...

Should the y be the lower bounder or top edge?

Could this be a issue?

On Fri, Jul 20, 2018 at 11:11 PM Gert Wollny <gert.wollny at collabora.com> wrote:
>
> 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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