[PATCH] drm/nouveau/nvif: fix null ptr deref on pre-fermi boards

[Danilo Krummrich]

On Mon Jul 14, 2025 at 4:59 AM CEST, Ben Skeggs wrote:
> Check that gpfifo.post() exists before trying to call it.
>
> Fixes: 862450a85b85 ("drm/nouveau/gf100-: track chan progress with non-WFI semaphore release")
> Reported-by: Jamie Heilman <jamie at audible.transient.net>
> Reported-by: Rui Salvaterra <rsalvaterra at gmail.com>
> Tested-by: Rui Salvaterra <rsalvaterra at gmail.com>
> Signed-off-by: Ben Skeggs <bskeggs at nvidia.com>

Please remember to add a Closes tag for Reported-by (I added them when I applied
the patch).

Applied to drm-misc-fixes, thanks!