Nouveau - Mar 2024 - [PATCH] drm/nouveau/dp: Fix incorrect return code in r535_dp_aux_xfer()

I've recently been seeing some unexplained GSP errors on my RTX 6000 from
failed aux transactions:

  [  132.915867] nouveau 0000:1f:00.0: gsp: cli:0xc1d00002 obj:0x00730000
  ctrl cmd:0x00731341 failed: 0x0000ffff

While the cause of these is not yet clear, these messages made me notice
that the aux transactions causing these transactions were succeeding - not
failing. As it turns out, this is because we're currently not returning the
correct variable when r535_dp_aux_xfer() hits an error - causing us to
never propagate GSP errors for failed aux transactions to userspace.

So, let's fix that.

Fixes: 4ae3a20102b2 ("nouveau/gsp: don't free ctrl messages on
errors")
Signed-off-by: Lyude Paul <lyude at redhat.com>
---
 drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
b/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
index 6a0a4d3b8902d..027867c2a8c5b 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
@@ -1080,7 +1080,7 @@ r535_dp_aux_xfer(struct nvkm_outp *outp, u8 type, u32
addr, u8 *data, u8 *psize)
 	ret = nvkm_gsp_rm_ctrl_push(&disp->rm.objcom, &ctrl,
sizeof(*ctrl));
 	if (ret) {
 		nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
-		return PTR_ERR(ctrl);
+		return ret;
 	}
 
 	memcpy(data, ctrl->data, size);
-- 
2.43.0

Reviewed-by: Dave Airlie <airlied at redhat.com>

On Sat, Mar 16, 2024 at 7:21?AM Lyude Paul <lyude at redhat.com>
wrote:
>
> I've recently been seeing some unexplained GSP errors on my RTX 6000
from
> failed aux transactions:
>
>   [  132.915867] nouveau 0000:1f:00.0: gsp: cli:0xc1d00002 obj:0x00730000
>   ctrl cmd:0x00731341 failed: 0x0000ffff
>
> While the cause of these is not yet clear, these messages made me notice
> that the aux transactions causing these transactions were succeeding - not
> failing. As it turns out, this is because we're currently not returning
the
> correct variable when r535_dp_aux_xfer() hits an error - causing us to
> never propagate GSP errors for failed aux transactions to userspace.
>
> So, let's fix that.
>
> Fixes: 4ae3a20102b2 ("nouveau/gsp: don't free ctrl messages on
errors")
> Signed-off-by: Lyude Paul <lyude at redhat.com>
> ---
>  drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
b/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
> index 6a0a4d3b8902d..027867c2a8c5b 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/engine/disp/r535.c
> @@ -1080,7 +1080,7 @@ r535_dp_aux_xfer(struct nvkm_outp *outp, u8 type, u32
addr, u8 *data, u8 *psize)
>         ret = nvkm_gsp_rm_ctrl_push(&disp->rm.objcom, &ctrl,
sizeof(*ctrl));
>         if (ret) {
>                 nvkm_gsp_rm_ctrl_done(&disp->rm.objcom, ctrl);
> -               return PTR_ERR(ctrl);
> +               return ret;
>         }
>
>         memcpy(data, ctrl->data, size);
> --
> 2.43.0
>