disable-gpu no longer works with M59

[Marshall Greenblatt]

Hi All,

I'm testing a Chromium-derived product at master revision 5be07ac8 (#464640) which is also the M59 branch point. I notice that the `--disable-gpu` command-line flag no longer stops the GPU process from launching (tested on Windows 10 and Ubuntu Linux 14.04). Is this a known issue and/or an intentional change? Is there an alternate flag that I should be using to disable GPU process launch (and thereby trigger software rendering)?

Thanks,

Marshall

[Victor Miura]

SwiftShader is now packaged in Chrome and is used for WebGL.  If you go to chrome://gpu , what features are enabled?

[Marshall Greenblatt]

Attached are chrome_gpu_default.pdf (no command-line flags) and chrome_gpu_disabled.pdf (--disable-gpu command-line flag) from Windows 10 64-bit. From the output it seems that most GPU features are disabled in the --disable-gpu case. However, the GPU process is still being launched in both cases.

Here is the GPU process command-line from the default case:

"C:\code\chromium_git\chromium\src\out\Debug_GN_x86\cefclient.exe" --type=gpu-process --lang=en-US --log-file="C:\code\chromium_git\chromium\src\out\Debug_GN_x86\debug.log" --supports-dual-gpus=false --gpu-driver-bug-workarounds=7,10,19,20,23,26,41,74 --disable-gl-extensions="GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent" --gpu-vendor-id=0x1002 --gpu-device-id=0x6821 --gpu-driver-vendor="Advanced Micro Devices, Inc." --gpu-driver-version=15.301.2101.0 --gpu-driver-date=2-9-2016 --lang=en-US --log-file="C:\code\chromium_git\chromium\src\out\Debug_GN_x86\debug.log" --service-request-channel-token=E4674A34ED2B8DDE643FD4DE99F9D1D6 --mojo-platform-channel-handle=1520 --ignored=" --type=renderer " /prefetch:2

And the --disable-gpu case:

"C:\code\chromium_git\chromium\src\out\Debug_GN_x86\cefclient.exe" --type=gpu-process --lang=en-US --log-file="C:\code\chromium_git\chromium\src\out\Debug_GN_x86\debug.log" --use-gl=swiftshader-webgl --supports-dual-gpus=false --gpu-driver-bug-workarounds=7,10,19,20,23,26,41,74 --disable-gl-extensions="GL_KHR_blend_equation_advanced GL_KHR_blend_equation_advanced_coherent" --disable-webrtc-hw-encoding --gpu-vendor-id=0x1002 --gpu-device-id=0x6821 --gpu-driver-vendor="Google Inc." --gpu-driver-version=3.3.0.2 --gpu-driver-date=2017/04/07 --lang=en-US --log-file="C:\code\chromium_git\chromium\src\out\Debug_GN_x86\debug.log" --service-request-channel-token=A9F77CF04F72D91CDE04ACFE230BEF23 --mojo-platform-channel-handle=2892 --ignored=" --type=renderer " /prefetch:2

So, it seems likely to be the swiftshader usage that you reference.

[Nicolas Capens]

This is now the expected behavior for --disable-gpu on Windows and desktop Linux. Note the GL_RENDERER string in about://gpu showing that it's using SwiftShader.

--disable-gpu is still the way to ensure the GPU won't be used. SwiftShader provides WebGL support on the CPU. But it does use the "GPU" process for it.

[Marshall Greenblatt]

OK, thanks for the confirmation. The main problem for me is that I can no longer work around https://bugs.chromium.org/p/chromium/issues/detail?id=699278 with --disable-gpu. Perhaps the amount of work performed in the GPU process can be further reduced for the swiftshader use case (or perhaps I just need to wait for that bug to be resolved :)).