Bug#616389: xserver-xorg-video-radeon: Crashes when closing graphical VT ("(EE) RADEON(0): failed to set mode: Permission denied")

[Michel Dänzer]

On Die, 2011-03-08 at 22:00 +0000, Thue Janus Kristensen wrote: 
> 
> With both drmDropMaster breakpointed in the second server,
> and drmSetMaster breakpointed in the first server, drmDropMaster is
> called first in the second server, and the first server doesn't reach
> drmSetMaster until after I continue the second server from the
> drmDropMaster breakpoint. No crash.
> 
> 
> With only drmSetMaster breakpointed in the first server, but the
> second server still running with gdb attached for consistency, there
> is no crash when I continue the first server from the drmSetMaster
> breakpoint.
> 
> 
> With both servers running inside gdb, but no breakpoints, it crashes.

So, apparently the problem is that drmSetMaster runs 'too early'...

How about if you only set a breakpoint on drmDropMaster in the second
server, and on hitting it just 'finish' the function before continuing.
Does the first server hit drmSetMaster before drmDropMaster has finished
in the second one?

BTW, did you also get any SIGUSR1 or other signals in either server
while doing this? If so, did you do the same for them as for SIGPIPE, to
prevent them from influencing the timing between drmDrop/SetMaster?


-- 
Earthling Michel Dänzer           |                http://www.vmware.com
Libre software enthusiast         |          Debian, X and DRI developer