Comment 125 for bug 252094

I used to have decent performance with Google Earth (GE) on Hardy, but after the upgrade to Intrepid I am having issues with rendering as well. Everything seems fine, but whenever I try to run GE or World Wind Java I get this single error message in /var/log/Xorg.0.log
(EE) intel(0): underrun on pipe B!

Below are additional outputs that I can think of... These are on a Lenovo 3000 v100 laptop.
$ lspci |grep gra
00:02.0 VGA compatible controller: Intel Corporation Mobile 945GM/GMS, 943/940GML Express Integrated Graphics Controller (rev 03)
00:02.1 Display controller: Intel Corporation Mobile 945GM/GMS/GME, 943/940GML Express Integrated Graphics Controller (rev 03)

$ glxgears -info
GL_RENDERER = Mesa DRI Intel(R) 945GM 20061102 x86/MMX/SSE2
GL_VERSION = 1.4 Mesa 7.2
GL_VENDOR = Tungsten Graphics, Inc
GL_EXTENSIONS = GL_ARB_depth_texture... GL_SUN_multi_draw_arrays
4161 frames in 5.0 seconds = 832.134 FPS
5007 frames in 5.0 seconds = 1001.400 FPS
4988 frames in 5.0 seconds = 997.439 FPS
4944 frames in 5.0 seconds = 988.700 FPS

I notice that even though DRI is enabled my CPU usage goes to 75% on one core when the GLXGears is running. When the window is behind another window rates go up to ~3200 FPS or 16000 frames over 5 sec. I don't recall these behaviors in Hardy.

$ glxinfo | grep render
direct rendering: Yes
OpenGL renderer string: Mesa DRI Intel(R) 945GM 20061102 x86/MMX/SSE2

In HARDY glxinfo would give me a different date for MESA:
direct rendering: Yes
OpenGL renderer string: Mesa DRI Intel(R) 945GM 20061017 x86/MMX/SSE2

May be MESA might have something to do with this?

I used to have flicker problems on Hardy when I run GE with Compiz, so I keep my compiz turned off. Though I tested to see if it was working and I don't seem to have problems with wobbly windows etc. They seem to work OK. Performance difference with/without DRI on Hardy was 6000/4000 frames with GLX gears and that made a huge difference in GE.

Just for the record, afaik GE needs SSE2 as well, and it is supported on the laptop.
$ cat /proc/cpuinfo | grep sse2 -o
sse2
sse2

In general the performance is OK, but seems like something went wrong with the 3D drivers... I hope the "buffer underrun" message in Xorg.log or the date difference in MESA drivers can give someone an idea to fix this.