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

[Lin, Wayne]

[AMD Public Use]

> -----Original Message-----
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> Sent: Tuesday, February 23, 2021 1:00 AM
> To: Lin, Wayne <Wayne.Lin at amd.com>
> Cc: dri-devel at lists.freedesktop.org; Brol, Eryk <Eryk.Brol at amd.com>; Zhuo, Qingqing <Qingqing.Zhuo at amd.com>;
> stable at vger.kernel.org; Zuo, Jerry <Jerry.Zuo at amd.com>; Kazlauskas, Nicholas <Nicholas.Kazlauskas at amd.com>; Dhinakaran
> Pandiyan <dhinakaran.pandiyan at 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 at amd.com>
> > Cc: stable at 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 at 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.
Appreciate for your time!
>
> >  else
> >  hdr->broadcast = 0;
> > --
> > 2.17.1
> >
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> --
> Ville Syrjälä
> Intel
Regards,
Wayne Lin