It would be really helpful if you would provide a test case that fails on your phone modeled after those in https://github.com/KhronosGroup/WebGL/tree/master/sdk/tests/conformance/glsl/bugs , similar to this one:

https://github.com/KhronosGroup/WebGL/blob/master/sdk/tests/conformance/glsl/bugs/conditional-discard-optimization.html

This is almost surely a driver bug triggered by some shader transformation being done by the browser.

Also, please provide the contents of about:gpu from your phone. Select and copy all the text from that web page and paste it into this bug report. Thanks.

ah yes, the good old "needs-food" label.

Please find attached :
- the about:gpu screenshot from my phone
- All files needed to reproduce bug, namely
   - chromewebgls6.htm - a very simplified test file
   - canvasmatrix4.js - the standard matrix processing
   - cubewithholes.png - the texture
I'm not familiar at all with the github test repository, so I hope the above will help.

Deleted: Screenshot_20171223-100225.jpg 4.0 MB

	Screenshot_20171223-100225.jpg 4.0 MB View Download

Deleted: chromewebgls6.htm 5.7 KB

chromewebgls6.htm 5.7 KB View Download

Deleted: canvasmatrix4.js 7.7 KB

canvasmatrix4.js 7.7 KB View Download

Deleted: cubewithholes.png 260 KB

	cubewithholes.png 260 KB View Download

Thank you for providing more feedback. Adding requester "kainino@chromium.org" to the cc list and removing "Needs-Feedback" label.

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

If this is in fact a regression in Chrome itself, then I suspect that it is due to a workarounds change. We will have to bisect this. I'll take it.

Bisecting.

Bisected to
https://chromium.googlesource.com/chromium/src/+/cdc786f5d2a2b538f4914ba0afbaee15634206b9
> Use 8x MSAA rather than 4x MSAA when available.

It seems this is another platform on which we should limit MSAA to 4x.

Thanks Kai and sorry for the trouble. In hindsight I probably should not have made this change unless the GPU is desktop class. Would you consider blacklisting on all Android?

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/687cb227f2d9a18d632a2657773b0a52889b1c49

commit 687cb227f2d9a18d632a2657773b0a52889b1c49
Author: Kai Ninomiya <kainino@chromium.org>
Date: Sat Apr 14 03:28:30 2018

Limit MSAA to 4x on Android devices

These devices tend to be hi-dpi, and low-power. 8x MSAA has also been
seen to trigger various bugs, and impacts performance on some devices.

Bug:  797243 ,  730303 
Change-Id: I41f1ef387009f1f63dff82ecb1f3737d3a0c22aa
Reviewed-on: https://chromium-review.googlesource.com/1013279
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550873}
[modify] https://crrev.com/687cb227f2d9a18d632a2657773b0a52889b1c49/gpu/config/gpu_driver_bug_list.json

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/687cb227f2d9a18d632a2657773b0a52889b1c49

commit 687cb227f2d9a18d632a2657773b0a52889b1c49
Author: Kai Ninomiya <kainino@chromium.org>
Date: Sat Apr 14 03:28:30 2018

Limit MSAA to 4x on Android devices

These devices tend to be hi-dpi, and low-power. 8x MSAA has also been
seen to trigger various bugs, and impacts performance on some devices.

Bug:  797243 ,  730303 
Change-Id: I41f1ef387009f1f63dff82ecb1f3737d3a0c22aa
Reviewed-on: https://chromium-review.googlesource.com/1013279
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Cr-Commit-Position: refs/heads/master@{#550873}
[modify] https://crrev.com/687cb227f2d9a18d632a2657773b0a52889b1c49/gpu/config/gpu_driver_bug_list.json

Should we merge this to M67 to improve overall driver stability? zmo@ suggested this in issue 657277.

Feel free to re-close this if you don't think it warrants a merge.

Added a merge request.
This seems to be a small patch and it will increase the overall driver stability in general.

This bug requires manual review: We are only 9 days from stable.
Please contact the milestone owner if you have questions.
Owners: cmasso@(Android), cmasso@(iOS), kbleicher@(ChromeOS), govind@(Desktop)

For more details visit https://www.chromium.org/issue-tracking/autotriage - Your friendly Sheriffbot

Can this wait for M68 instead?

Approving the merge since this is blocking a RBS  issue 833463 

 issue 833463  doesn't seem to be RBS. Can you re-review?

I agree that it would be best to merge this back. It's a very small and safe blacklisting entry change. Apologies for not requesting merge much earlier.

Thanks! Since this does not seem to be a regression in M67, let's not take the risk to merge it unless you think the fix is very safe and can cause any new issue.

Indeed, it is an earlier regression. However I don't know exactly how large the impact is.

vikas/zmo, was there a specific reason that this came up? would you like to push for merge?

We have a bunch of Android crashes that we don't know the cause. We believe reducing the sample count from 8 to 4 will reduce vram pressure on many Android devices and therefore increase GPU stability in general.

This is a very safe tiny CL and its impact could be big. I strongly suggest we take this to beta.

cmasso@, please confirm it's OK for us to merge back.

Please merge back if this is very safe

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/fc3de2e7d607be28983f8e60a1d258ea1036d054

commit fc3de2e7d607be28983f8e60a1d258ea1036d054
Author: Kai Ninomiya <kainino@chromium.org>
Date: Tue May 22 22:11:22 2018

Limit MSAA to 4x on Android devices

These devices tend to be hi-dpi, and low-power. 8x MSAA has also been
seen to trigger various bugs, and impacts performance on some devices.

Bug:  797243 ,  730303 
Change-Id: I41f1ef387009f1f63dff82ecb1f3737d3a0c22aa
Reviewed-on: https://chromium-review.googlesource.com/1013279
Reviewed-by: Kenneth Russell <kbr@chromium.org>
Commit-Queue: Kai Ninomiya <kainino@chromium.org>
Cr-Original-Commit-Position: refs/heads/master@{#550873}(cherry picked from commit 687cb227f2d9a18d632a2657773b0a52889b1c49)
Reviewed-on: https://chromium-review.googlesource.com/1069422
Reviewed-by: Zhenyao Mo <zmo@chromium.org>
Cr-Commit-Position: refs/branch-heads/3396@{#680}
Cr-Branched-From: 9ef2aa869bc7bc0c089e255d698cca6e47d6b038-refs/heads/master@{#550428}
[modify] https://crrev.com/fc3de2e7d607be28983f8e60a1d258ea1036d054/gpu/config/gpu_driver_bug_list.json

Thanks Mo!