Olivier Langlois's blog

Here is what I have done:

1. Enable crossfire
2. Start x
3. Start tracing X with strace
4. execute glxinfo
5. Boom!

The last entry in my trace log is:

ioctl(13, 0xc03064a6

where 13 is a file descriptor to fglrx fs frontend.

lrwx------ 1 root root 64 May 24 23:36 13 -> /dev/ati/card0
lrwx------ 1 root root 64 May 24 23:36 14 -> /dev/ati/card1
lrwx------ 1 root root 64 May 24 23:36 15 -> /dev/ati/card0
lrwx------ 1 root root 64 May 24 23:36 16 -> /dev/ati/card0
lrwx------ 1 root root 64 May 24 23:36 17 -> /dev/ati/card0

Next step will be activate kernel profiling, with some luck, maybe I'll find out that this is a simple to fix deadlock in spinlocks located on the public side of the driver.

In the meantime, this exercise did allow me to find out that the catalyst X driver was doing silly things. Such as totally rewrite the amdpcsdb file several times in the span of about a minute:

lano1106@Wailaba2 /dev/snd $ grep amdpcsdb /nas/x_trace.out
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33
open("/etc/ati/amdpcsdb", O_WRONLY|O_CREAT|O_TRUNC, 0666) = 33

and reading a 3 bytes file containing " \n" 5 times:

lano1106@whippet2 /etc/ati $ ls -l atiapfxx.blb
-rw-r--r-- 1 root root 3 Apr 27 15:35 atiapfxx.blb
lano1106@whippet2 /etc/ati $ grep 'atiapfxx.blb' /nas/x_trace.out
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33
open("/etc/ati/atiapfxx.blb", O_RDONLY) = 33