Re: [PATCH 2/2] drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Tue, Feb 23, 2021 at 05:32:36AM +0000, Lin, Wayne wrote:
> [AMD Public Use]
> 
> > -----Original Message-----
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > Sent: Tuesday, February 23, 2021 1:00 AM
> > To: Lin, Wayne <Wayne.Lin@amd.com>
> > Cc: dri-devel@lists.freedesktop.org; Brol, Eryk <Eryk.Brol@amd.com>; Zhuo, Qingqing <Qingqing.Zhuo@amd.com>;
> > stable@vger.kernel.org; Zuo, Jerry <Jerry.Zuo@amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas@amd.com>; Dhinakaran
> > Pandiyan <dhinakaran.pandiyan@intel.com>
> > Subject: Re: [PATCH 2/2] drm/dp_mst: Set CLEAR_PAYLOAD_ID_TABLE as broadcast
> >
> > On Mon, Feb 22, 2021 at 12:00:27PM +0800, Wayne Lin wrote:
> > > [Why & How]
> > > According to DP spec, CLEAR_PAYLOAD_ID_TABLE is a path broadcast
> > > request message and current implementation is incorrect. Fix it.
> > >
> > > Signed-off-by: Wayne Lin <Wayne.Lin@amd.com>
> > > Cc: stable@vger.kernel.org
> > > ---
> > >  drivers/gpu/drm/drm_dp_mst_topology.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > index 713ef3b42054..6d73559046e5 100644
> > > --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> > > +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> > > @@ -1072,6 +1072,7 @@ static void build_clear_payload_id_table(struct
> > > drm_dp_sideband_msg_tx *msg)
> > >
> > >  req.req_type = DP_CLEAR_PAYLOAD_ID_TABLE;
> > >  drm_dp_encode_sideband_req(&req, msg);
> > > +msg->path_msg = true;
> > >  }
> > >
> > >  static int build_enum_path_resources(struct drm_dp_sideband_msg_tx
> > > *msg, @@ -2722,7 +2723,8 @@ static int set_hdr_from_dst_qlock(struct
> > > drm_dp_sideband_msg_hdr *hdr,
> > >
> > >  req_type = txmsg->msg[0] & 0x7f;
> > >  if (req_type == DP_CONNECTION_STATUS_NOTIFY ||
> > > -req_type == DP_RESOURCE_STATUS_NOTIFY)
> > > +req_type == DP_RESOURCE_STATUS_NOTIFY ||
> > > +req_type == DP_CLEAR_PAYLOAD_ID_TABLE)
> > >  hdr->broadcast = 1;
> >
> > Looks correct.
> > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Hmm. Looks like we're missing DP_POWER_DOWN_PHY and DP_POWER_UP_PHY here as well. We do try to send them as path
> > requests, but apparently forget to mark them as broadcast messages.
> Hi Ville,
> I also look up the spec but DP_POWER_DOWN_PHY & DP_POWER_UP_PHY seems to be defined as path or node request only. Not broadcast message. Please correct me if I'm wrong here.

Doh. Yeah, you're correct. Not sure what section I was reading earlier
when I came to that conclusion.

> Appreciate for your time!
> >
> > >  else
> > >  hdr->broadcast = 0;
> > > --
> > > 2.17.1
> > >
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> >
> > --
> > Ville Syrjälä
> > Intel
> Regards,
> Wayne Lin

-- 
Ville Syrjälä
Intel