[Nouveau] [BUG][NOUVEAU] G70 broken since 5.10-rc1

[Mark Hounschell]

I'm running an older "NVIDIA Corporation G70 [GeForce 7800 GT] (rev a1)" 
card in a newer BIOSTAR B550GTA MB. Kernel 5.10-rcx does not work. I get 
no virtual consoles or X screen.


My dmesg seems to show the cause:

[    5.825702] fb0: switching to nouveaufb from VESA VGA
[    6.242991] nouveau 0000:14:00.0: vgaarb: deactivate vga console
[    6.243066] nouveau 0000:14:00.0: NVIDIA G70 (047200a1)
[    6.443671] nouveau 0000:14:00.0: bios: version 05.70.02.13.7b
[    6.443948] nouveau 0000:14:00.0: fb: 256 MiB GDDR3
[    6.498039] nouveau 0000:14:00.0: DRM: VRAM: 250 MiB
[    6.498041] nouveau 0000:14:00.0: DRM: GART: 512 MiB
[    6.498044] nouveau 0000:14:00.0: DRM: TMDS table version 1.1
[    6.498046] nouveau 0000:14:00.0: DRM: DCB version 3.0
[    6.498049] nouveau 0000:14:00.0: DRM: DCB outp 00: 01000300 00000028
[    6.498051] nouveau 0000:14:00.0: DRM: DCB outp 01: 03000302 00000000
[    6.498053] nouveau 0000:14:00.0: DRM: DCB outp 02: 04011310 00000028
[    6.498055] nouveau 0000:14:00.0: DRM: DCB outp 03: 04011312 00000000
[    6.498057] nouveau 0000:14:00.0: DRM: DCB outp 04: 020223f1 0040c080
[    6.498060] nouveau 0000:14:00.0: DRM: DCB conn 00: 1030
[    6.498062] nouveau 0000:14:00.0: DRM: DCB conn 01: 2130
[    6.498064] nouveau 0000:14:00.0: DRM: DCB conn 02: 0210
[    6.498065] nouveau 0000:14:00.0: DRM: DCB conn 03: 0211
[    6.498067] nouveau 0000:14:00.0: DRM: DCB conn 04: 0213
[    6.502949] nouveau 0000:14:00.0: DRM: Setting dpms mode 3 on TV 
encoder (output 4)
[    6.585845] nouveau 0000:14:00.0: DRM: failed to map fb: -28
[    6.585949] [drm] Initialized nouveau 1.3.1 20120801 for 0000:14:00.0 
on minor 0

This commit caused the BUG

141b15e59175aa174ca1f7596188bd15a7ca17ba is the first bad commit
commit 141b15e59175aa174ca1f7596188bd15a7ca17ba
Author: Christian König <christian.koenig at amd.com>
Date:   Fri Aug 21 16:06:50 2020 +0200

     drm/nouveau: move io_reserve_lru handling into the driver v5

     While working on TTM cleanups I've found that the io_reserve_lru 
used by
     Nouveau is actually not working at all.

     In general we should remove driver specific handling from the memory
     management, so this patch moves the io_reserve_lru handling into 
Nouveau
     instead.

     v2: don't call ttm_bo_unmap_virtual in nouveau_ttm_io_mem_reserve
     v3: rebased and use both base and offset in the check
     v4: fix small typos and test the patch
     v5: rebased and keep the mem.bus init in TTM.

     Signed-off-by: Christian König <christian.koenig at amd.com>
     Acked-by: Daniel Vetter <daniel.vetter at ffwll.ch>
     Reviewed-by: Ben Skeggs <bskeggs at redhat.com>
     Link: https://patchwork.freedesktop.org/patch/388643/

  drivers/gpu/drm/nouveau/nouveau_bo.c  | 101 
+++++++++++++++++++++++++++-------
  drivers/gpu/drm/nouveau/nouveau_bo.h  |   3 +
  drivers/gpu/drm/nouveau/nouveau_drv.h |   2 +
  drivers/gpu/drm/nouveau/nouveau_ttm.c |  44 ++++++++++++++-
  4 files changed, 127 insertions(+), 23 deletions(-)