Re: Radeon KMS regression still present in 2.6.33-rc6

From: Linus Torvalds
Date: Sat Jan 30 2010 - 12:44:56 EST




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
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