Bug 110295

Created attachment 143835 [details] [review]
fix_flicker_workaround

hi. Could you please do few things for me please?
I found out, that flickering disappear, if I turn off Vsync. I confirmed this behaviour for system 18.3.5 and built from source 19.1.0 mesa versions.

I can say that ultra-low settings and minimum resolution leads to quite playable game.

My configuration:
OS Fedora 29
Mesa (18.3.5, 19.1.0)
Kernel 4.20.16
gpu Skylake (HD 520)

Also, if I apply this patch (attached to issue) - problem disappears for me (in both cases, with Vsync and without).
So this leads me to idea that it is the same problem with 
https://bugs.freedesktop.org/show_bug.cgi?id=109630
https://bugs.freedesktop.org/show_bug.cgi?id=109616

One more thing - in case if I exchange driver (applying compiled manually instead of system) - game needs about 5-10 minutes to start (loading screen displays).
In case of system mesa version - game starts fast.

Comment on attachment 143835 [details] [review]
fix_flicker_workaround

>diff --git a/src/intel/vulkan/genX_cmd_buffer.c b/src/intel/vulkan/genX_cmd_buffer.c
>index e5daf8b037d..2fc73435161 100644
>--- a/src/intel/vulkan/genX_cmd_buffer.c
>+++ b/src/intel/vulkan/genX_cmd_buffer.c
>@@ -2771,6 +2771,7 @@ genX(cmd_buffer_flush_state)(struct anv_cmd_buffer *cmd_buffer)
>    if (cmd_buffer->state.descriptors_dirty)
>       dirty = flush_descriptor_sets(cmd_buffer);
> 
>+   cmd_buffer->state.push_constants_dirty |= VK_SHADER_STAGE_ALL_GRAPHICS;
>    if (dirty || cmd_buffer->state.push_constants_dirty) {
>       /* Because we're pushing UBOs, we have to push whenever either
>        * descriptors or push constants is dirty.

Created attachment 143836 [details] [review]
workaround_patch_CORRECT

I am sorry, first patch was sent with mistake. Added correct one:
workaround_patch_CORRECT

I did the test with disabling vsync but it did not fix the problems to me, they were still happening, but with Mesa with this patch applied, then the game worked correctly without the blinking elements. I have seen no graphical problem anywhere in the game with this patch applied.

Here, the 10 minutes loading only happens when I use a certain Mesa version for the first time, the second time using the same Mesa version is used the game opens fast.

hm, interesting (about vsync). But in total - if patch helped, I think, this may mean that it has same or similar root of problem with Witcher3 and VKQuake

Hey Leozinho, could you please check this issue in the game on latest master mesa?

I checked Witcher and vkQuake, both were fixed with:

commit bc612536eb2f0f77725103e53077ad5a28036ac3 (HEAD -> master, origin/master, origin/HEAD)
Author: Jason Ekstrand <jason@jlekstrand.net>
Date:   Wed Jul 31 10:42:24 2019 -0500

    anv: Emit a dummy MEDIA_VFE_STATE before switching from GPGPU to 3D
    
    There is an object-level  preemption workaround which requires this.
    However, even without object-level preemption, we seem to have issues
    with geometry flickering when 3D and compute are combined in the same
    batch and this appears to fix it.
    
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=109630
    Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=111267
    Cc: mesa-stable@lists.freedesktop.org
    Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

Created attachment 144988 [details]
Backtrace

I tried testing DiRT 4 and I got the most strange crash I've ever seen. Using Mesa 19.2.0-devel (git-5a898e2a65), on Steam logs, a bit before the crash, the following appeared:

SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    1388 bytes into the SPIR-V binary
SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    2500 bytes into the SPIR-V binary
SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    2588 bytes into the SPIR-V binary
SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    2676 bytes into the SPIR-V binary
SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    2800 bytes into the SPIR-V binary
SPIR-V WARNING:
    In file ../src/compiler/spirv/spirv_to_nir.c:826
    Decoration not allowed on struct members: SpvDecorationRestrict
    2856 bytes into the SPIR-V binary

And then the game crashed with a segmentation fault. The backtrace, which is really strange, is attached. As the game is crashing when trying to start a stage, I can't test if this bug was fixed.

Also, there is the following in dmesg:

[368518.106893] traps: IdxD3D11_1[25466] general protection ip:7f4dbb871b10 sp:7f4d2e7d64b0 error:0 in libvulkan_intel.so[7f4dbb5c1000+541000]
[368760.788230] traps: IdxD3D11_1[30128] general protection ip:7fffafa99b10 sp:7fff23fd94b0 error:0 in libvulkan_intel.so[7fffaf7e9000+541000]
[368980.314952] traps: IdxD3D11_1[2320] general protection ip:7fffafa99b10 sp:7fff25fdd4b0 error:0 in libvulkan_intel.so[7fffaf7e9000+541000]

As this blinking elements bug was present on Elite Dangerous too, I tested Mesa 19.2.0-devel (git-5a898e2a65) with Elite Dangerous. In that game, there were no blinking elements, so it seems this bug is fixed.

Regarding DiRT 4, should I report this DiRT 4 crash as a new bug? The backtrace is really unhelpful.

>Regarding DiRT 4, should I report this DiRT 4 crash as a new bug? The backtrace is really unhelpful.

thank you for feedback! Let me then find the game one more time (one friend had it on steam acc :) and reproduce.

I think it would be correct to open a new one, as it doesn't relate to artifacts in this bug report.

good news. Game is crashing only on Debug mesa.

Built release one on this commit - 

commit 5e38db0c47ca57c6e904f44d0d0e9ef299d14f3c (HEAD -> master, origin/master, origin/HEAD)
Author: Tapani Pälli <tapani.palli@intel.com>
Date:   Thu Aug 8 14:57:14 2019 +0300

Game works fine, and flickering wasn't observed. I checked on max screen settings with and without vSync.
I created new ticket => https://bugs.freedesktop.org/show_bug.cgi?id=111339

Leozinho, you may try "release" flag for mesa. From my side confirming the fix.

I have tested Mesa 19.3.0-devel (git-eea6f21cbd) and, while the loading is longer, now it no longer crashes. The flickering also no longer exists, the game is working correctly.

so, the final message is:

fixed with

commit bc612536eb2f0f77725103e53077ad5a28036ac3 (HEAD -> master, origin/master, origin/HEAD)
Author: Jason Ekstrand <jason@jlekstrand.net>
Date:   Wed Jul 31 10:42:24 2019 -0500

    anv: Emit a dummy MEDIA_VFE_STATE before switching from GPGPU to 3D