[Public] Hi Jeff, Thanks. I might need more information to understand why we can't retrieve the drm atomic state. Also , "Failed to create MST payload for port" indicates error while configuring DPCD payload ID table. Could you help to provide log with KMS + ATOMIC + DP debug on please? Thanks in advance! Regards, Wayne > -----Original Message----- > From: Alex Deucher <alexdeucher@xxxxxxxxx> > Sent: Thursday, April 13, 2023 8:59 PM > To: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>; Lin, Wayne > <Wayne.Lin@xxxxxxx> > Cc: Jeff Layton <jlayton@xxxxxxxxxx>; David Airlie <airlied@xxxxxxxxx>; > Daniel Vetter <daniel@xxxxxxxx>; Deucher, Alexander > <Alexander.Deucher@xxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx; dri- > devel@xxxxxxxxxxxxxxxxxxxxx > Subject: Re: [PATCH] drm: make drm_dp_add_payload_part2 gracefully > handle NULL state pointer > > + Wayne > > On Thu, Apr 13, 2023 at 8:31 AM Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx> > wrote: > > > > On Thu, 13 Apr 2023, Jeff Layton <jlayton@xxxxxxxxxx> wrote: > > > I've been experiencing some intermittent crashes down in the display > > > driver code. The symptoms are ususally a line like this in dmesg: > > > > > > amdgpu 0000:30:00.0: [drm] Failed to create MST payload for port > > > 000000006d3a3885: -5 > > > > > > ...followed by an Oops due to a NULL pointer dereference. > > > > > > The real bug is probably in the caller of this function, which is > > > passing it a NULL state pointer, but this patch at least keeps my > > > machine from oopsing when this occurs. > > > > My fear is that papering over this makes the root cause harder to find. > > > > Cc: Harry, Alex > > > > > > BR, > > Jani. > > > > > > > > > > Link: https://bugzilla.redhat.com/show_bug.cgi?id=2184855 > > > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx> > > > --- > > > drivers/gpu/drm/display/drm_dp_mst_topology.c | 3 ++- > > > 1 file changed, 2 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c > > > b/drivers/gpu/drm/display/drm_dp_mst_topology.c > > > index 38dab76ae69e..87ad406c50f9 100644 > > > --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c > > > +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c > > > @@ -3404,7 +3404,8 @@ int drm_dp_add_payload_part2(struct > > > drm_dp_mst_topology_mgr *mgr, > > > > > > /* Skip failed payloads */ > > > if (payload->vc_start_slot == -1) { > > > - drm_dbg_kms(state->dev, "Part 1 of payload creation for %s > failed, skipping part 2\n", > > > + drm_dbg_kms(state ? state->dev : NULL, > > > + "Part 1 of payload creation for %s failed, > > > + skipping part 2\n", > > > payload->port->connector->name); > > > return -EIO; > > > } > > > > -- > > Jani Nikula, Intel Open Source Graphics Center
