Created attachment 16427 [details]
Xorg.0.log

after an upgrade from slackware 12.0 to 12.1, X process is using a lot of cpu power for simple operations. for example, simply switching between two application windows (on a freshly started machine) can raise it's cpu usage to 80 and more %.

the problem is reproducible with i810 and vesa drivers.
it happens both with (i915) and without in-kernel dri support.
reproducible with kernels 2.6.24.5, 2.6.25 and 2.6.25.2 (while not appearing with previous xorg version on 2.6.25 and earlier).
intel framebuffer driver is enabled in the kernel and used for vt.

i believe this is a different problem from bug 2952, as the original problem is solved and other problem involves nvidia binary driver.

attached are xorg logfile and configuration file. note, logfile says this is prerelease, but judging from the date, that's one day before actual release, so i suspect it's an rc who was then released unmodified or something like that :)

lspci -v for the video adapter :
00:00.0 Host bridge: Intel Corporation 82845G/GL[Brookdale-G]/GE/PE DRAM Controller/Host-Hub Interface (rev 03)
        Subsystem: GVC/BCM Advanced Research Unknown device 2179
        Flags: bus master, fast devsel, latency 0
        Memory at e0000000 (32-bit, prefetchable) [size=128M]
        Capabilities: [e4] Vendor Specific Information <?>
        Kernel driver in use: agpgart-intel

grep "model name" /proc/cpuinfo
model name      : Intel(R) Celeron(R) CPU 2.20GHz