| Message ID | 20220329080526.1583458-1-Wayne.Lin@amd.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | drm/dp_mst: Lower down debug info level when receive NAK | expand |
On 2022-03-29 04:05, Wayne Lin wrote: > [Why] > It's reasonable that we receive NAK while doing DP_REMOTE_DPCD_READ. > Downstream device might reply NAK with the reason and source should > react accordingly. > > e.g. > 1. When downstream device can't handle corresponding message in time, > it then replies NAK as reason been set as DEFER. > 2. When multi-function branch-sink device doesn't enumerate virtual > DP peer devices for those multi-function down facing ports. Without > virtual DPCD, branch device might reply NAK with reason as BAD_PARAM > indicating this port can't do aux DPCD read. > > It's expected result. Not an error. > > [How] > Use drm_dbg_kms() to replace drm_err() when receive NAK. > > Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> Reviewed-by: Harry Wentland <harry.wentland@amd.com> Harry > --- > drivers/gpu/drm/dp/drm_dp_mst_topology.c | 3 +-- > 1 file changed, 1 insertion(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/dp/drm_dp_mst_topology.c b/drivers/gpu/drm/dp/drm_dp_mst_topology.c > index 11300b53d24f..764a6b59bc1e 100644 > --- a/drivers/gpu/drm/dp/drm_dp_mst_topology.c > +++ b/drivers/gpu/drm/dp/drm_dp_mst_topology.c > @@ -3557,9 +3557,8 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr, > if (ret < 0) > goto fail_free; > > - /* DPCD read should never be NACKed */ > if (txmsg->reply.reply_type == 1) { > - drm_err(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n", > + drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n", > mstb, port->port_num, offset, size); > ret = -EIO; > goto fail_free;
diff --git a/drivers/gpu/drm/dp/drm_dp_mst_topology.c b/drivers/gpu/drm/dp/drm_dp_mst_topology.c index 11300b53d24f..764a6b59bc1e 100644 --- a/drivers/gpu/drm/dp/drm_dp_mst_topology.c +++ b/drivers/gpu/drm/dp/drm_dp_mst_topology.c @@ -3557,9 +3557,8 @@ static int drm_dp_send_dpcd_read(struct drm_dp_mst_topology_mgr *mgr, if (ret < 0) goto fail_free; - /* DPCD read should never be NACKed */ if (txmsg->reply.reply_type == 1) { - drm_err(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n", + drm_dbg_kms(mgr->dev, "mstb %p port %d: DPCD read on addr 0x%x for %d bytes NAKed\n", mstb, port->port_num, offset, size); ret = -EIO; goto fail_free;
[Why] It's reasonable that we receive NAK while doing DP_REMOTE_DPCD_READ. Downstream device might reply NAK with the reason and source should react accordingly. e.g. 1. When downstream device can't handle corresponding message in time, it then replies NAK as reason been set as DEFER. 2. When multi-function branch-sink device doesn't enumerate virtual DP peer devices for those multi-function down facing ports. Without virtual DPCD, branch device might reply NAK with reason as BAD_PARAM indicating this port can't do aux DPCD read. It's expected result. Not an error. [How] Use drm_dbg_kms() to replace drm_err() when receive NAK. Signed-off-by: Wayne Lin <Wayne.Lin@amd.com> --- drivers/gpu/drm/dp/drm_dp_mst_topology.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)