Re: [PATCH v3 2/3] drm/nouveau/gsp/r570: Never enter Gcoff state

[Danilo Krummrich]

(Cc: John)

On Wed Jul 1, 2026 at 8:17 PM CEST, Lyude Paul wrote:
> It turns out that the only reason our previous fixes looked like they
> worked for this was because we would occasionally set the Gcoff state to 0
> in the normal S3 path, which fixed suspend/resume on desktops - but not on
> machines using runtime suspend.
>
> The proper fix is to just never set this flag. Our current guess for the
> reasoning behind this is that Gcoff likely coincides with GC6, and not
> literally power off.

I don't think GcOff coincides with GC6, it should actually be a power off.

>From a quick glance in OpenRM, it seems that with bEnteringGcoffState = 1 it
also saves off buffers flagged as MEMDESC_FLAGS_LOST_ON_SUSPEND.

My guess would be that with bEnteringGcoffState = 1, GSP's resume path expects
certain kernel-driver-allocated buffers to still be in place that nouveau didn't
save off, or rather never had in the first place.

John, do you have some details about this?

> Signed-off-by: Lyude Paul <lyude@xxxxxxxxxx>
> Fixes: 53dac0623853 ("drm/nouveau/gsp: add support for 570.144")
> Cc: <stable@xxxxxxxxxxxxxxx> # v6.16+
> ---
>  drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r570/fbsr.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r570/fbsr.c b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r570/fbsr.c
> index 2945d5b4e5707..af5aa5065c3dd 100644
> --- a/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r570/fbsr.c
> +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r570/fbsr.c
> @@ -81,7 +81,7 @@ r570_fbsr_init(struct nvkm_gsp *gsp, struct sg_table *sgt, u64 size)
>  	ctrl->hClient = gsp->internal.client.object.handle;
>  	ctrl->hSysMem = memlist.handle;
>  	ctrl->sysmemAddrOfSuspendResumeData = gsp->sr.meta.addr;
> -	ctrl->bEnteringGcoffState = 1;
> +	ctrl->bEnteringGcoffState = 0;
>  
>  	ret = nvkm_gsp_rm_ctrl_wr(&gsp->internal.device.subdevice, ctrl);
>  	if (ret)
> -- 
> 2.54.0