[webkit-dev] layout tests cannot set Generic RGB Color Profile on headless MacPro?

Simon Fraser simon.fraser at apple.com
Fri Oct 7 11:53:56 PDT 2011

On Oct 7, 2011, at 11:45 AM, Elliot Poger wrote:

> I was having problems with lots of image mismatches running WebKit layout tests on a headless MacPro (10.6.8).  (The image diffs were very minor adjustments in scroll bar shading.)
> Eventually, out of frustration, I tried running the same test on that headless MacPro as well as my desktop MacPro (also 10.6.8).  The test succeeded on my desktop MacPro but not the headless MacPro.
> One difference I have noticed is that the Display Profile (under System Preferences > Displays > Color) is set to "sRGB IEC61966-2.1" (my desktop was set to "Generic RGB Profile").  I tried setting it to "Generic RGB Profile" on the headless machine, but when I closed and reopened System Preferences it had reverted to "sRGB IEC61966-2.1".
> I tried setting the Display Profile on my desktop to "sRGB IEC61966-2.1", and the color scheme was noticeably brighter... but when I ran layout tests afterwards, I saw that layout tests automatically set the profile back to "Generic RGB Profile" temporarily for the test.  When I run layout tests on the headless MacPro, it seems that it fails to change the color profile (and I don't see any error in the output of layout tests).
> I tried it on a headless Mac Mini (10.6.8) and there layout tests was able to change to Generic RGB Profile (and thus the tests passed).
> For now, my fix is going to be: don't run layout tests on headless MacPros; use headless MacMinis instead.  Is this a Known Issue?  Any suggestions?

I'm aware that there are color profile issues when running pixel tests, but I was not aware of differences between hardware.

We may be able to fix DumpRenderTree/WebKitTestRunner to change the color profile just for the test window, and not globally. I haven't tried that yet.

Finally, I've noticed some changes in color profile behavior on Lion, so if you try running tests there, you may see a new set of problems.


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