Nouveau - Sep 2019 - [PATCH 4.19 092/190] drm/nouveau: Dont WARN_ON VCPI allocation failures

[ Upstream commit b513a18cf1d705bd04efd91c417e79e4938be093 ]

This is much louder then we want. VCPI allocation failures are quite
normal, since they will happen if any part of the modesetting process is
interrupted by removing the DP MST topology in question. So just print a
debugging message on VCPI failures instead.

Signed-off-by: Lyude Paul <lyude at redhat.com>
Fixes: f479c0ba4a17 ("drm/nouveau/kms/nv50: initial support for DP 1.2
multi-stream")
Cc: Ben Skeggs <bskeggs at redhat.com>
Cc: dri-devel at lists.freedesktop.org
Cc: nouveau at lists.freedesktop.org
Cc: <stable at vger.kernel.org> # v4.10+
Signed-off-by: Ben Skeggs <bskeggs at redhat.com>
Signed-off-by: Sasha Levin <sashal at kernel.org>
---
 drivers/gpu/drm/nouveau/dispnv50/disp.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
b/drivers/gpu/drm/nouveau/dispnv50/disp.c
index f889d41a281fa..5e01bfb69d7a3 100644
--- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
+++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
@@ -759,7 +759,8 @@ nv50_msto_enable(struct drm_encoder *encoder)
 
 	slots = drm_dp_find_vcpi_slots(&mstm->mgr, mstc->pbn);
 	r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port, mstc->pbn,
slots);
-	WARN_ON(!r);
+	if (!r)
+		DRM_DEBUG_KMS("Failed to allocate VCPI\n");
 
 	if (!mstm->links++)
 		nv50_outp_acquire(mstm->outp);
-- 
2.20.1

Hi Greg,

This feels like it's missing a From: line.

commit b513a18cf1d705bd04efd91c417e79e4938be093
Author: Lyude Paul <lyude at redhat.com>
Date:   Mon Jan 28 16:03:50 2019 -0500

    drm/nouveau: Don't WARN_ON VCPI allocation failures

Is this an artifact of your notification-of-patches process and I
never noticed before, or was the patch ingested incorrectly?

Cheers,

  -ilia

On Fri, Sep 13, 2019 at 9:16 AM Greg Kroah-Hartman
<gregkh at linuxfoundation.org> wrote:
>
> [ Upstream commit b513a18cf1d705bd04efd91c417e79e4938be093 ]
>
> This is much louder then we want. VCPI allocation failures are quite
> normal, since they will happen if any part of the modesetting process is
> interrupted by removing the DP MST topology in question. So just print a
> debugging message on VCPI failures instead.
>
> Signed-off-by: Lyude Paul <lyude at redhat.com>
> Fixes: f479c0ba4a17 ("drm/nouveau/kms/nv50: initial support for DP 1.2
multi-stream")
> Cc: Ben Skeggs <bskeggs at redhat.com>
> Cc: dri-devel at lists.freedesktop.org
> Cc: nouveau at lists.freedesktop.org
> Cc: <stable at vger.kernel.org> # v4.10+
> Signed-off-by: Ben Skeggs <bskeggs at redhat.com>
> Signed-off-by: Sasha Levin <sashal at kernel.org>
> ---
>  drivers/gpu/drm/nouveau/dispnv50/disp.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c
b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> index f889d41a281fa..5e01bfb69d7a3 100644
> --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c
> +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c
> @@ -759,7 +759,8 @@ nv50_msto_enable(struct drm_encoder *encoder)
>
>         slots = drm_dp_find_vcpi_slots(&mstm->mgr, mstc->pbn);
>         r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port,
mstc->pbn, slots);
> -       WARN_ON(!r);
> +       if (!r)
> +               DRM_DEBUG_KMS("Failed to allocate VCPI\n");
>
>         if (!mstm->links++)
>                 nv50_outp_acquire(mstm->outp);
> --
> 2.20.1
>
>
>
> _______________________________________________
> dri-devel mailing list
> dri-devel at lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

On Fri, Sep 13, 2019 at 09:33:36AM -0400, Ilia Mirkin
wrote:
>Hi Greg,
>
>This feels like it's missing a From: line.
>
>commit b513a18cf1d705bd04efd91c417e79e4938be093
>Author: Lyude Paul <lyude at redhat.com>
>Date:   Mon Jan 28 16:03:50 2019 -0500
>
>    drm/nouveau: Don't WARN_ON VCPI allocation failures
>
>Is this an artifact of your notification-of-patches process and I
>never noticed before, or was the patch ingested incorrectly?
It was always like this for patches that came through me. Greg's script
generates an explicit "From:" line in the patch, but I never saw the
value in that since git does the right thing by looking at the "From:"
line in the mail header.

The right thing is being done in stable-rc and for the releases. For
your example here, this is how it looks like in the stable-rc tree:

commit bdcc885be68289a37d0d063cd94390da81fd8178
Author:     Lyude Paul <lyude at redhat.com>
AuthorDate: Mon Jan 28 16:03:50 2019 -0500
Commit:     Greg Kroah-Hartman <gregkh at linuxfoundation.org>
CommitDate: Fri Sep 13 14:05:29 2019 +0100

    drm/nouveau: Don't WARN_ON VCPI allocation failures

--
Thanks,
Sasha