hybrid-graphics-linux team mailing list archive

[Stefan Dröge <stefan@xxxxxxxxxx>]

Hi guys!
As already mentioned in another thread, I'm a user of a Thinkpad E520
with muxless switchable graphics. I tried to investigate what goes
wrong when Xorg tries to use the fglrx driver and fails with the error
message "invalid video bios signature".
So I tried to dump the video BIOS like that:
stefan@TE520:~$ echo 1 | sudo tee
/sys/devices/pci0000\:00/0000\:00\:01.0/0000\:01\:00.0/rom
stefan@TE520:~$ sudo cat
/sys/devices/pci0000\:00/0000\:00\:01.0/0000\:01\:00.0/rom >
vbios_ati.rom

However this fails with the error message: "cat:
/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0/rom: Input/output
error"

Doing the same with the intel card works.

So now I think: Is this the cause (i.e. the fglrx driver relies on the
same method to read the video BIOS, but since reading the video bios
fails, the signature is obviously wrong) or just another symptom for
the same problem (i.e. fglrx uses another method for reading the video
bios, that works more or less, however switchable graphics is just
quirky and the problem is somewhere else)?
What is your opinion? Can you replicate the problem on your system? Is
this specific to muxless solutions / laptop brands /AMD hybrid
solutions?

fyi: http://smackerelofopinion.blogspot.com/2011/07/using-pci-sysfs-interface-to-dump-video.html

Thanks, Stefan