"When switching to the tab with HTML5 video, it doesn't display for a couple of seconds, and CPU is at 100% for that time.  Scrolling is incredibly jerky, with pauses of a few seconds between"

Didn't finish my sentence, should say something like: Scrolling is incredibly jerky, a sequence of jumps with pauses of a few seconds between each.

can't reproduce with NVIDIA drivers

Can you reproduce with nouveau?  I can't reproduce on my laptop with "Intel Corporation Mobile GM965/GL960 Integrated Graphics Controller".  So my guess is still that it's a nouveau issue, but I don't have a second NVIDIA-running machine handy to prove or disprove.

Can you try running with --disable-accelerated-compositing and seeing if it's any smoother/more responsive?

Moving to mstone:x until we have an actionable issue.

Yes, the problem disappears if I do that.

(That is, the problem disappears if I run with --disable-accelerated-compositing.)

Hmmm!!!  vrk maybe this is a general issue with accelerated compositing..

noveau is experimental driver which doesn't support full 2D and 3D acceleration. Accelerated compositing works with nvidia and intel drivers.

Right.  Chromium should probably just treat nouveau for now as though there's no acceleration.  However, there are experimental nouveau versions that use Gallium3D, which does do real hardware acceleration, and that should eventually become standard.  I don't have any idea what the right way is to check for this is, though -- probably not just "check if driver is nouveau", that's not futureproof.

Given our current velocity, we need to punt 500 bugs from m9.  Moving p2 bugs, that are not started and have an owner to the next milestone.  If this issue absolutely needs to be fixed in the current milestone please move it back, however, at this time the focus should be on p1 bugs.

Sound like we we have a candidate for blacklisting: http://nouveau.freedesktop.org/wiki/

Related to  issue 58182 

Googling suggests this formula to check if software rendering is being used on Linux:

$ glxinfo | grep renderer
OpenGL renderer string: Software Rasterizer

There's probably some better way for Chrome to get this info, so it can detect all software rendering on Linux without having to check for particular drivers.  Just checking for nouveau is a bad idea because 1) there are experimental versions of nouveau that do use hardware support via Gallium3D, and distros will eventually make those default; and 2) there are other graphics drivers that do software rendering on Linux, I think.

Disclaimer: I don't actually know much about Linux graphics (or graphics generally), so much of the above might be wrong.  But I'm pretty sure blacklisting nouveau isn't the right answer here.

P2 bugs with an owner that are not marked as started are being automatically moved to mstone:11.

Simetrical,  can you provide the following information.

1) glxinfo full output
2) lspci -v | grep VGA

Thanks.

2) try lspci -nn | grep VGA instead.  with -nn I get the vendor/device IDs.

$ lspci -nn | grep VGA
02:00.0 VGA compatible controller [0300]: nVidia Corporation G84 [GeForce 8600 GT] [10de:0402] (rev a1)

glxinfo attached.

glxinfo 20.1 KB View Download

Great.  Thanks!

I think at the moment the best thing to do is to disable accelerated-compositing if gl renderer string contains the word "software".

After r72502, we won't use accelerated compositing if renderer is software-based.

Confirmed fixed in 11.0.672.2 dev.

The problem has reappeared for me as of 12.0.742.16 dev.  Again, --disable-accelerated-compositing is needed to get a usable browser when <video> is on the page.  It's the same computer/OS/drivers/etc. as before, except I've upgraded to Ubuntu 10.10 in the interim.

Can you open about:gpu page and copy the output here?  I don't think we made any changes that could affect your machine, so I am curious why the issue reappeared.

Right now:

Graphics Feature Status
Canvas: Software rendered. Hardware acceleration not enabled.
3D CSS: Unavailable. Hardware acceleration unavailable
Compositing: Software only. Hardware acceleration disabled.
WebGL: Hardware accelerated
WebGL multisampling: Hardware accelerated
Problems Detected
Accelerated 2D canvas has not been enabled (in about:flags or command line)
Accelerated compositing has been disabled, either via about:flags or command line
Version Information
Data exported	Fri May 20 2011 16:05:00 GMT-0400 (EDT)
Chrome version	13.0.761.0 (Official Build 84747) dev
Software rendering list version	1.10
Driver Information
Initialization time	0
Vendor Id	0x10de
Device Id	0x0402
Driver vendor	
Driver version	
Driver date	
Pixel shader version	
Vertex shader version	
GL version	
GL_VENDOR	
GL_RENDERER	
GL_VERSION	
GL_EXTENSIONS	
Log Messages
[25700:25700:12793286050511:INFO:gl_implementation.cc(95)] : Using desktop GL implementation.
[25700:25700:12793286110553:INFO:gpu_child_thread.cc(132)] : gpu_info_collector::CollectGraphicsInfo complete


When I remove the --disable-accelerated-compositing flag:

Graphics Feature Status
Canvas: Software rendered. Hardware acceleration not enabled.
3D CSS: Hardware accelerated
Compositing: Hardware accelerated
WebGL: Hardware accelerated
WebGL multisampling: Hardware accelerated
Problems Detected
Accelerated 2D canvas has not been enabled (in about:flags or command line)
Version Information
Data exported	Fri May 20 2011 16:06:21 GMT-0400 (EDT)
Chrome version	13.0.767.1 (Official Build 85531) dev
Software rendering list version	1.10
Driver Information
Initialization time	0
Vendor Id	0x10de
Device Id	0x0402
Driver vendor	
Driver version	
Driver date	
Pixel shader version	
Vertex shader version	
GL version	
GL_VENDOR	
GL_RENDERER	
GL_VERSION	
GL_EXTENSIONS	
Log Messages
[26085:26085:12793369932265:INFO:gl_implementation.cc(95)] : Using desktop GL implementation.
[26085:26085:12793369974201:INFO:gpu_child_thread.cc(132)] : gpu_info_collector::CollectGraphicsInfo complete

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