Re: drm causes kernel panic

On Wed, 2008-09-03 at 12:58 -0700, Steve Kargl wrote:
> On Wed, Sep 03, 2008 at 03:51:52PM -0400, Robert Noland wrote:
> > On Tue, 2008-09-02 at 22:12 -0700, Steve Kargl wrote:
> >> 
> >> From dmesg:
> >> 
> >> vgapci0: <VGA display> port 0xb000-0xb0ff mem 0xfd000000-0xfdffffff,0
> >> xfeaff000-0xfeafffff irq 18 at device 6.0 on pci3
> >> drm0: <Rage XL> on vgapci0
> >> info: [drm] Initialized mach64 2.0.0 20060718
> > 
> > Ok, I've found the problem... It is easy enough to fix your specific
> > situation, but doing so will cause problems for other drivers...  Which
> > is the reason that I made that change to begin with.  The big problem is
> > that drm_pci_alloc gets called from a variety of places, some of which
> > already hold locks while others don't.  We aren't allowed to hold locks
> > over some of the bus_dma functions, so I have to go through all of these
> > paths and figure out if it is generally safe to always drop the locks,
> > or if I need to restructure the code somehow...  If you want a patch to
> > just get you going temporarily, just let me know...
> > 
> 
> I can disable Xorg's dri module.  When you have a patch you're happy
> with, feel free to ping me for testing.

Ok, please try the attached patch.  I talked it over with another drm
developer and it should be safe to drop all the locks while calling
drm_pci_alloc().  I think I have fixed this for all drivers / paths that
call it.  It will log an error now if it is called with either of the
two locks that I found being held.  I have tested this on my intel 965gm
so far and all is well.  I also had to touch mach64 and radeon, so I
need someone to validate those.  (This is a different path from the
panic you received previously)

robert.