Oops with Radeon/Uninorth on Maple

[Dmitry Eremin-Solenikov <dmitry_eremin@mentor.com>]

Hello, colleagues,

I'm trying to enable an AGP slot (again) on my Maple board (dual 
PPC970FX board, with CPC925 (U3H) north bridge).

  For now I'm stuck with a problem: I use radeon card, drm-radeon driver 
with KMS.

If I force drm-radeon to think about a card as about PCI card (by 
commenting corresponding lines in drm_radeon_kms.c), everything works, I 
get framebuffer, working X11, etc. If I enable agpgart-uninorth driver
and RADEON_IS_AGP flag in drm driver, I get an Oops early during the 
bootstrap. Relevant part of the log (I can send full dmesg of normal 
bootstrap or this oops on request, if that would help).

[    2.820647] Linux agpgart interface v0.103
[    2.824909] agpgart-uninorth 0000:f0:0b.0: Apple U3H chipset
[    2.830668] agpgart-uninorth 0000:f0:0b.0: Found device u3, rev 35
[    2.843611] agpgart-uninorth 0000:f0:0b.0: configuring for size idx: 64
[    2.850638] agpgart-uninorth 0000:f0:0b.0: AGP aperture is 256M @ 0x0
[    2.857646] [drm] Initialized drm 1.1.0 20060810
[    2.862567] [drm] radeon defaulting to kernel modesetting.
[    2.868091] [drm] radeon kernel modesetting enabled.
[    2.873222] radeon 0000:f0:10.0: enabling device (0000 -> 0003)
[    2.880311] radeon 0000:f0:10.0: enabling bus mastering
[    2.885591] [drm] initializing kernel modesetting (RV350 
0x1002:0x4152 0x18BC:0x0416).
[    2.893629] [drm] register mmio base: 0xD0020000
[    2.898260] [drm] register mmio size: 65536
[    2.947112] [drm] GPU not posted. posting now...
[    3.051033] agpgart-uninorth 0000:f0:0b.0: putting AGP V3 device into 
8x mode
[    3.058197] radeon 0000:f0:10.0: putting AGP V3 device into 8x mode
[    3.064666] radeon 0000:f0:10.0: GTT: 256M 0x00000000 - 0x0FFFFFFF
[    3.070864] [drm] Generation 2 PCI interface, using max accessible memory
[    3.077672] radeon 0000:f0:10.0: VRAM: 128M 0x00000000C0000000 - 
0x00000000C7FFFFFF (128M used)
[    3.086487] [drm] Supports vblank timestamp caching Rev 1 (10.10.2010).
[    3.093126] [drm] Driver supports precise vblank timestamp query.
[    3.099291] [drm] radeon: irq initialized.
[    3.103404] [drm] Detected VRAM RAM=128M, BAR=128M
[    3.108214] [drm] RAM width 128bits DDR
[    3.112263] [TTM] Zone  kernel: Available graphics memory: 496682 kiB
[    3.118732] [TTM] Initializing pool allocator
[    3.123346] [drm] radeon: 128M of VRAM memory ready
[    3.128256] [drm] radeon: 256M of GTT memory ready.
[    3.133295] [drm] radeon: ib pool ready.
[    3.137708] [drm] radeon: 1 quad pipes, 1 Z pipes initialized.
[    3.144018] radeon 0000:f0:10.0: WB disabled
[    3.148326] [drm] fence driver on ring 0 use gpu addr 0x00000000 and 
cpu addr 0xd000000000066000
[    3.157474] [drm] Loading R300 Microcode
[    3.162480] [drm] radeon: ring at 0x0000000000001000
[    3.167569] [drm] ring test succeeded in 0 usecs
cpu 0x0: Vector: 200 (Machine Check) at [c000000000d63aa0]
     pc: c0000000000cc07c: .trace_hardirqs_on_caller+0x6c/0x190
     lr: c0000000000152f4: .cpu_idle+0x1a4/0x220
     sp: c000000000d63d20
    msr: 9000000000009032
   current = 0xc000000000c4db30
   paca    = 0xc00000000ffff000   softe: 0        irq_happened: 0x01
     pid   = 0, comm = swapper/0
enter ? for help
[c000000000d63db0] c0000000000152f4 .cpu_idle+0x1a4/0x220
[c000000000d63e50] c000000000008fb8 .rest_init+0xe8/0x110
[c000000000d63ee0] c000000000ba2998 .start_kernel+0x3e4/0x408
[c000000000d63f90] c000000000007558 .start_here_common+0x20/0x48
0:mon> x
[  843.783295] Oops: Machine check, sig: 7 [#1]
[  843.787589] SMP NR_CPUS=4 Maple
[  843.790768] Modules linked in:
[  843.793855] NIP: c0000000000cc07c LR: c0000000000152f4 CTR: 
c000000000023eac
[  843.800920] REGS: c000000000d63aa0 TRAP: 0200   Not tainted  (3.4.0+)
[  843.807376] MSR: 9000000000009032 <SF,HV,EE,ME,IR,DR,RI>  CR: 
24222222  XER: 00000006
[  843.815412] SOFTE: 0
[  843.817607] TASK = c000000000c4db30[0] 'swapper/0' THREAD: 
c000000000d60000 CPU: 0
[  843.825035] GPR00: 0000000000000000 c000000000d63d20 c000000000d63280 
c0000000000152f4
[  843.833169] GPR04: 0000000000000000 c000000000099d10 0000000000000001 
0000000000000002
[  843.841302] GPR08: 0100000000000000 c000000000e828e8 0140000000000000 
0000000000000000
[  843.849436] GPR12: 0000000044222282 c00000000ffff000 0000000000000000 
0000000000000000
[  843.857570] GPR16: 0000000000ff8750 0000000000cdc890 00000000010001e0 
0000000000000000
[  843.865702] GPR20: 0000000000000000 0000000000000000 000000001dcd6500 
0000000000000000
[  843.873835] GPR24: 0000000000000000 0000000000ec7b00 9000000000009032 
c000000000d7b178
[  843.881979] GPR28: c000000000d7b278 0000000000000008 c000000000c970f8 
c0000000000152f4
[  843.890314] NIP [c0000000000cc07c] .trace_hardirqs_on_caller+0x6c/0x190
[  843.896942] LR [c0000000000152f4] .cpu_idle+0x1a4/0x220
[  843.902181] Call Trace:
[  843.904640] [c000000000d63d20] [c000000000d63db0] 
init_thread_union+0x3db0/0x4000 (unreliable)
[  843.913317] [c000000000d63db0] [c0000000000152f4] .cpu_idle+0x1a4/0x220
[  843.919964] [c000000000d63e50] [c000000000008fb8] .rest_init+0xe8/0x110
[  843.926615] [c000000000d63ee0] [c000000000ba2998] 
.start_kernel+0x3e4/0x408
[  843.933611] [c000000000d63f90] [c000000000007558] 
.start_here_common+0x20/0x48
[  843.940866] Instruction dump:
[  843.943868] 40de00a4 e92d01c8 800908e8 2f800000 40de0094 e93e8098 
80090000 2f800000
[  843.951829] 409e0030 880d01f2 2fa00000 40de00b0 <e93e84e8> 88090000 
2f800000 40de00c8


Looking for any suggestions on this.

-- 
With best wishes
Dmitry