* [PATCH] V2: Currently, DRM get the capability of the mst hub only from DP_DPCD_REV and get the slower speed even the mst hub can run in the faster speed.
@ 2020-09-10 6:36 Koba Ko
2020-09-10 17:48 ` Lyude Paul
0 siblings, 1 reply; 2+ messages in thread
From: Koba Ko @ 2020-09-10 6:36 UTC (permalink / raw)
To: Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
David Airlie, Daniel Vetter, Lyude Paul, dri-devel, linux-kernel
Cc: anthony.wong
As per DP-1.3, First check DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT.
If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 1, read the DP_DP13_DPCD_REV to
get the faster capability.
If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 0, read DP_DPCD_REV.
Signed-off-by: Koba Ko <koba.ko@canonical.com>
---
ChangeLog:
1. use drm_dp_read_dpcd_caps instead.
---
drivers/gpu/drm/drm_dp_mst_topology.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c b/drivers/gpu/drm/drm_dp_mst_topology.c
index 7753c718ddf9..293f71d0ae90 100644
--- a/drivers/gpu/drm/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/drm_dp_mst_topology.c
@@ -3694,8 +3694,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct drm_dp_mst_topology_mgr *mgr, bool ms
((dpcd_ext & DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT) ? DP_DP13_DPCD_REV : DP_DPCD_REV);
/* get dpcd info */
- ret = drm_dp_dpcd_read(mgr->aux, dpcd_offset, mgr->dpcd, DP_RECEIVER_CAP_SIZE);
- if (ret != DP_RECEIVER_CAP_SIZE) {
+ ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
+ if (ret < 0) {
DRM_DEBUG_KMS("failed to read DPCD\n");
goto out_unlock;
}
--
2.25.1
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] V2: Currently, DRM get the capability of the mst hub only from DP_DPCD_REV and get the slower speed even the mst hub can run in the faster speed.
2020-09-10 6:36 [PATCH] V2: Currently, DRM get the capability of the mst hub only from DP_DPCD_REV and get the slower speed even the mst hub can run in the faster speed Koba Ko
@ 2020-09-10 17:48 ` Lyude Paul
0 siblings, 0 replies; 2+ messages in thread
From: Lyude Paul @ 2020-09-10 17:48 UTC (permalink / raw)
To: Koba Ko, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann,
David Airlie, Daniel Vetter, dri-devel, linux-kernel
Cc: anthony.wong
The commit message should be shorter and follow the format other commits for
drm usually do, in this case something like:
drm/dp_mst: Retrieve extended DPCD caps for topology manager
On Thu, 2020-09-10 at 14:36 +0800, Koba Ko wrote:
> As per DP-1.3, First check DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT.
> If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 1, read the DP_DP13_DPCD_REV to
> get the faster capability.
> If DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT is 0, read DP_DPCD_REV.
>
> Signed-off-by: Koba Ko <koba.ko@canonical.com>
> ---
> ChangeLog:
> 1. use drm_dp_read_dpcd_caps instead.
> ---
> drivers/gpu/drm/drm_dp_mst_topology.c | 4 ++--
> 1 file changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_dp_mst_topology.c
> b/drivers/gpu/drm/drm_dp_mst_topology.c
> index 7753c718ddf9..293f71d0ae90 100644
> --- a/drivers/gpu/drm/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/drm_dp_mst_topology.c
> @@ -3694,8 +3694,8 @@ int drm_dp_mst_topology_mgr_set_mst(struct
> drm_dp_mst_topology_mgr *mgr, bool ms
> ((dpcd_ext & DP_EXTENDED_RECEIVER_CAP_FIELD_PRESENT)
> ? DP_DP13_DPCD_REV : DP_DPCD_REV);
>
> /* get dpcd info */
> - ret = drm_dp_dpcd_read(mgr->aux, dpcd_offset, mgr->dpcd,
> DP_RECEIVER_CAP_SIZE);
> - if (ret != DP_RECEIVER_CAP_SIZE) {
> + ret = drm_dp_read_dpcd_caps(mgr->aux, mgr->dpcd);
> + if (ret < 0) {
> DRM_DEBUG_KMS("failed to read DPCD\n");
Let's use drm_dbg_kms() here, and let's also print the return code when this
fails.
With those things fixed:
Reviewed-by: Lyude Paul <lyude@redhat.com>
> goto out_unlock;
> }
--
Cheers,
Lyude Paul (she/her)
Software Engineer at Red Hat
^ permalink raw reply [flat|nested] 2+ messages in thread
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2020-09-10 6:36 [PATCH] V2: Currently, DRM get the capability of the mst hub only from DP_DPCD_REV and get the slower speed even the mst hub can run in the faster speed Koba Ko
2020-09-10 17:48 ` Lyude Paul
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