Re: [PATCH v4 2/3] drm/nouveau/gsp/r570: Set GcOff = 1 in fbsr
From: lyude
Date: Mon Jul 27 2026 - 14:17:55 EST
aaaaand I completely forgot to change this from a 1 to 0 in the patch
title ._.
Reviewers - I will make sure this gets fixed before pushing it upstream
On Mon, 2026-07-27 at 13:47 -0400, Lyude Paul wrote:
> Previously, it looked as if we were able to fix suspend/resume on
> some
> desktops by setting Gcoff based on whether or not we were entering
> runtime
> PM. This was a mistake though - the only time suspend/resume would
> end up
> actually working was if Gcoff = 0.
>
> It seems like it's likely the main reason for this is the FBSR GcOff
> argument actually controls GSP's behavior with regards to which
> buffers it
> decides to save across suspend/resume. When GcOff = 1, RM reserved
> regions
> are saved unless they are marked as LOST_ON_SUSPEND, and RM channel-
> context
> and kernel-client buffers are also saved -including- when they are
> LOST_ON_SUSPEND. This means with GcOff = 1, we end up having GSP save
> and
> restore buffers that actually need to be reinitialized on resume -
> causing
> the failures we're setting.
>
> In the long term, we do want to have GcOff = 1 as there are still a
> handful
> of edge cases around broken runtime PM that I've seen on laptops -
> and I
> have a strong guess that actually properly implementing the required
> bits
> for enabling GcOff will probably address a number of those issues.
> For now
> though, disabling GcOff results in runtime PM being dramatically more
> stable then it was before.
>
> Thanks to John Hubbard from Nvidia for providing some background on
> what
> these options do in the GSP firmware do!
>
> 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)