REGRESSION: fast/canvas/webgl/context-attributes-alpha.html fails after bug 217212
Created attachment 411306 [details] Patch
Comment on attachment 411306 [details] Patch View in context: https://bugs.webkit.org/attachment.cgi?id=411306&action=review > Source/WebCore/ChangeLog:10 > + WebGLLayer contentsOpaque. Neither the EWS nor the local testing Why is. that?
Committed r268446: <https://trac.webkit.org/changeset/268446> All reviewed patches have been landed. Closing bug and clearing flags on attachment 411306 [details].
<rdar://problem/70284915>
>> + WebGLLayer contentsOpaque. Neither the EWS nor the local testing > Why is. that? It is unclear at this point, I'll investigate this more. The knowns: - I developed the patch on iMac with AMD card. I thought I ran the tests as supposed. - I noticed the regression on MacBook Pro with Intel/AMD, with automatic switching on - EWS runs Intel opus - Intel GPUs have bugs around IOSurfaces and their alpha channels. ANGLE tries to work around them. - The test and the expected.html both use the WebGL canvas alpha feature, which turned out to have the bug - The test should be run on Mac and expected to work - The -expected.html probably should not use the exact same code as what the test is testing, but it's somewhat tricky to alter the content in GPU-agnostic way The unknowns: - Did I run the tests locally? - Does Intel alpha bugs, ANGLE workarounds and the bug in question cancel each other out in EWS? - Does EWS run fast/canvas/webgl/context-attributes-alpha.html - If the bugs cancel each other out, why don't they cancel out with my MacBook Pro? Does it use the AMD part or are the drivers different or is there a bug in ANGLE workaround selection. I'll try to investigate the unknowns
To clarify, EWS is Mac Pros with AMD GPUs.
Bots that saw this failure were all newer AMD ones: iMac20,1 iMac19,1 MacBookPro15,3 MacBookPro16,1