[Mesa-dev] virgl and vc4 problem on Android

[Rob Clark]

On Wed, Jun 15, 2016 at 8:34 PM, Rob Herring <robh at kernel.org> wrote:
> In the process of adding RGBX (XB24) format to mesa for Android, I
> started seeing a new problem that makes the UI stop updating. It
> happens about when the splash screen is stopped and the lock screen is
> displayed. The display flickers on mouse movement, and it looks like
> the screen is flipping to old buffers (like the splash screen after
> its process exited). It is working fine for freedreno AFAICT, but I am
> running into a problem with virgl. With virgl, I get the following
> error:
>
> vrend_create_surface: context error reported 1 "surfaceflinger"
> Illegal resource 1435
> vrend_report_buffer_error: context error reported 1 "surfaceflinger"
> Illegal command buffer 329729
>
> The addition of the pixel format changes the eglconfig used for the
> splash screen. If I force the splash screen eglconfig to have an alpha
> or draw one frame of the splash screen and exit early or disable the
> splash screen, everything seems fine though I have hit the problem
> rarely navigating around. I suspect this has nothing to do with the
> pixel format other than different buffer sizes cause buffers to get
> reused differently.
>
> Now I've started working on getting RPi3 and vc4 working, and it
> appears to have a similar problem. I'm getting these errors though
> things go haywire before getting any error message:
>
> [   43.846569] [drm:vc4_submit_cl_ioctl] *ERROR* Failed to look up GEM BO 0: 4

at least in the vc4 case, I suspect you need a similar bit of winsys
magic to ensure the same pipe_screen is returned for any given drm
device fd.  (Or did someone already add that?)

In both virgl and vc4 case, you need to make sure that shared
(exported/imported) buffers don't end up in the bo cache.

That is at least what occurs to me off the top of my head.  Beyond
that, I'd have to look at code.  But it does sound a lot like the same
old handle <-> buffer confusion..

BR,
-R

> Here's a screenshot[1]. I've also seen an error for fbo size of 4KB
> when expected size is 5MB. The RPi is a bit different in that I can
> continue to navigate around, but apps are not really working and don't
> render completely. Returning to the home screen starts the flickering
> like the pic except the old contents are the app that ran last.
>
> Any suggestions on how to debug this? I've tried a few things like
> disabling the BO cache in vc4 gallium driver and logging BO
> create/free, but didn't see anything.
>
> Rob
>
> [1] https://goo.gl/photos/zqq3ksMVXLvbA6CK8