+ccameron and khushalsagar, graphics peeps

Marshall, can you go to chrome://gpu/ and attach the report?

Chris, can you take a look? Marshall is an old-school Mac friend of mine and is willing to give us a hand in diagnosis.

Marshall, you also indicated in the email to me that this seemed to be a recent regression. Am I reading your email correctly as to that? Do you know a rough timetable of when this started?

Attached GPU report

Deleted: GPU Report.txt 9.3 KB

GPU Report.txt 9.3 KB View Download

> Marshall, you also indicated in the email to me that this seemed to be a recent regression. Do you know a rough timetable of when this started?

Not exactly. I'm guessing within the lsat six weeks. Most of the stuttering/static appears in videos on Facebook, and my FB using is ... periodic. I can go weeks w/o logging in there.

In the short term, you should manually disable hardware acceleration by going to chrome://settings and toggling "Use hardware acceleration when available." 

This GPU should be blacklisted (its drivers are beyond bit-rotted), but for some reason the blacklist isn't taking.
+zmo +capn

WRT the blacklist logic:

This is reported on:
    Chrome version: 71.0.3578.98 
    VENDOR = 0x10de
    DEVICE = 0x0640 (NVIDIA GeForce GT 120 OpenGL Engine OpenGL 3.3 core)

Note that http://crrev.com/590516 explicitly blacklists everything that has GL <4.1, and that patch landed in 71.0.3551.0 [0] (and was merged back to 70).

But in about:gpu, I see:
    Graphics Feature Status
    Canvas: Hardware accelerated
    Compositing: Hardware accelerated
...
    GL_VENDOR:     Google Inc.
    GL_RENDERER:   ANGLE (NVIDIA Corporation NVIDIA GeForce GT 120 OpenGL Engine OpenGL 3.3 core)
    GL_VERSION:    OpenGL ES 2.0 (ANGLE 2.1.0.f2ed299569c0)
    GL_EXTENSIONS: ...

I believe that I should be seeing:
    Graphics Feature Status
    Canvas: Software only, hardware acceleration unavailable
    Compositing: Software only. Hardware acceleration disabled

Any idea how we're missing the fact that this GPU has as GL < 4.1?

zmo@ added a stronger blacklist at at [2], but it doesn't include the device 0x0640.

[0] https://storage.googleapis.com/chromium-find-releases-static/a36.html#a361a69018d5b46ba3a29f7818e717451a92a09f
[1] https://cs.chromium.org/chromium/src/gpu/config/software_rendering_list.json?rcl=7631a97395e88a9a4c2b880d540deb0626fe3078&l=1229
[2] https://cs.chromium.org/chromium/src/gpu/config/software_rendering_list.json?rcl=7631a97395e88a9a4c2b880d540deb0626fe3078&l=1702

> In the short term, you should manually disable hardware acceleration by going to chrome://settings and toggling "Use hardware acceleration when available." 

I've done that; and things are "better". There's still some weird video artifacts.
I'll see what happens after I reboot.

I don't understand this: why we are running on top of ANGLE on Mac? Did you pass in --use-gl=angle somewhere? I don't see the flag in about:gpu. passthrough command decoder also says false, so what's going on here?

geofflang@: any insights?

Corentin and I investigated and it turns out that ANGLE accidentally started shipping on Mac when Swiftshader was turned on!
 - https://chromium-review.googlesource.com/c/chromium/src/+/1005017/ Sets use_egl to be true on Mac
 - ANGLE is bundled as long as use_egl is true https://cs.chromium.org/chromium/src/chrome/BUILD.gn?l=979

Then, when desktop GL core profile fails to initialize (likely due to the blacklist), it falls back to the next implementation... Which happens to be ANGLE on Mac: https://cs.chromium.org/chromium/src/ui/gl/init/gl_factory_mac.cc?q=gl_factory_mac.cc&l=67

Based on this, I'm guessing that we're always falling back to ANGLE instead of Swiftshader on Mac since May.  I'm very surprised that there haven't been more issues and my best guess is that this situation is no worse than before the blacklist entry was added.  This video issue in particular doesn't appear to be due to using GL.

Do we have metrics on the GL renderer strings being seen on different platforms to get an idea of how many people are affected?

Ideally we can fix the fallback but leave ANGLE in the packaged libraries since we do plan on shipping it and there hasn't been a significant size regression to trigger complaints.

Ok, looked a bit more and we're actually pretty safe here.  We're entering this case because:
 - InitializeGLOneOffHelper in gl_factory.cc removes   kGLImplementationDesktopGLCoreProfile when the disable_es3_gl_context feature is on: https://cs.chromium.org/chromium/src/ui/gl/init/gl_factory.cc?l=39 
 - ANGLE is second in the list of allowed GL implementations after kGLImplementationDesktopGLCoreProfile
 - disable_es3_gl_context is used on Mac ONLY for the NVidia GeForce GT 120 GPU: https://cs.chromium.org/chromium/src/gpu/config/gpu_driver_bug_list.json?q=disable_es3_gl_context&dr=C&l=2651

So in the end, this bug only affects users with a NVidia GeForce GT 120 GPU.

Ewwwww, such a mess :)