The patch below does not apply to the 4.19-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From b513a18cf1d705bd04efd91c417e79e4938be093 Mon Sep 17 00:00:00 2001
From: Lyude Paul lyude@redhat.com Date: Mon, 28 Jan 2019 16:03:50 -0500 Subject: [PATCH] drm/nouveau: Don't WARN_ON VCPI allocation failures
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@redhat.com Fixes: f479c0ba4a17 ("drm/nouveau/kms/nv50: initial support for DP 1.2 multi-stream") Cc: Ben Skeggs bskeggs@redhat.com Cc: dri-devel@lists.freedesktop.org Cc: nouveau@lists.freedesktop.org Cc: stable@vger.kernel.org # v4.10+ Signed-off-by: Ben Skeggs bskeggs@redhat.com
diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index e8bb35f6d015..3f618ed4ec6f 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -817,7 +817,8 @@ nv50_msto_enable(struct drm_encoder *encoder)
r = drm_dp_mst_allocate_vcpi(&mstm->mgr, mstc->port, armh->dp.pbn, armh->dp.tu); - WARN_ON(!r); + if (!r) + DRM_DEBUG_KMS("Failed to allocate VCPI\n");
if (!mstm->links++) nv50_outp_acquire(mstm->outp);