Re: Radeon KMS regression still present in 2.6.33-rc6

[Linus Torvalds <torvalds@linux-foundation.org>]

On Sat, 30 Jan 2010, Kevin Winchester wrote:
>
> I took a picture of the crash details:
>
> http://picasaweb.google.ca/kjwinchester/LinuxKernelPanic#5432580230065271634
> 
> In case it helps, here is the gdb listing for the problem address:
> 
> (gdb) l *(radeon_agp_init+0x1d)
> 0xffffffff811c1592 is in radeon_agp_init (drivers/gpu/drm/radeon/radeon_agp.c:136).
> 131		uint32_t agp_status;
> 132		int default_mode;
> 133		bool is_v3;
> 134		int ret;
> 135	
> 136		if (rdev->ddev->agp->agp_info.aper_size < 32) {
> 137			dev_warn(rdev->dev, "AGP aperture to small (%dM) "
> 138				"need at least 32M, disabling AGP\n",
> 139				rdev->ddev->agp->agp_info.aper_size);
> 140			return -EINVAL;
> 
> Is there any other info I can provide?

In your crash 'rdev->ddev->agp' is NULL. The instruction decode is:

   e:	55                   	push   %rbp
   f:	48 89 e5             	mov    %rsp,%rbp
  12:	41 56                	push   %r14
  14:	41 55                	push   %r13
  16:	41 54                	push   %r12
  18:	53                   	push   %rbx
  19:	48 89 fb             	mov    %rdi,%rbx
  1c:	48 83 ec 40          	sub    $0x40,%rsp
  20:	48 8b 7f 08          	mov    0x8(%rdi),%rdi
  24:	48 8b 87 20 03 00 00 	mov    0x320(%rdi),%rax
  2b:*	4c 8b 60 28          	mov    0x28(%rax),%r12     <-- trapping instruction
  2f:	49 83 fc 1f          	cmp    $0x1f,%r12
  33:	77 2e                	ja     0x63
  35:	48 8b 3b             	mov    (%rbx),%rdi
  38:	48 8b 5f 10          	mov    0x10(%rdi),%rbx

so it's that lod of "agp_info.aper_size" that fails (you can see how it's 
trying to compare with 31, it comes from that "agp_info.aper_size < 32" 
thing.

Did that DRM init happen before AGP init or something?

		Linus