Re: [RESEND v3 1/6] drm/mst: read sideband messaging cap
On 3/19/24 10:20, Jani Nikula wrote:
On Tue, 19 Mar 2024, Jani Nikula wrote:
Amend drm_dp_read_mst_cap() to return an enum, indicating "SST", "SST
with sideband messaging", or "MST". Modify all call sites to take the
new return value into account.
drm-misc and nouveau maintainers, ack for merging this via drm-intel,
please?
Sure, please go ahead.
Thanks,
Danilo
BR,
Jani.
v2:
- Rename enumerators (Ville)
Cc: Arun R Murthy
Cc: Ville Syrjälä
Cc: Karol Herbst
Cc: Lyude Paul
Cc: Danilo Krummrich
Reviewed-by: Ville Syrjälä
Signed-off-by: Jani Nikula
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 20 ++--
drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
drivers/gpu/drm/nouveau/nouveau_dp.c | 2 +-
include/drm/display/drm_dp_mst_helper.h | 23 ++-
4 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 03d528209426..c193be3577f7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -3608,24 +3608,30 @@ fixed20_12 drm_dp_get_vc_payload_bw(const struct
drm_dp_mst_topology_mgr *mgr,
EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
/**
- * drm_dp_read_mst_cap() - check whether or not a sink supports MST
+ * drm_dp_read_mst_cap() - Read the sink's MST mode capability
* @aux: The DP AUX channel to use
* @dpcd: A cached copy of the DPCD capabilities for this sink
*
- * Returns: %True if the sink supports MST, %false otherwise
+ * Returns: enum drm_dp_mst_mode to indicate MST mode capability
*/
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
-const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux,
+const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
u8 mstm_cap;
if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
- return false;
+ return DRM_DP_SST;
if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, _cap) != 1)
- return false;
+ return DRM_DP_SST;
+
+ if (mstm_cap & DP_MST_CAP)
+ return DRM_DP_MST;
+
+ if (mstm_cap & DP_SINGLE_STREAM_SIDEBAND_MSG)
+ return DRM_DP_SST_SIDEBAND_MSG;
- return mstm_cap & DP_MST_CAP;
+ return DRM_DP_SST;
}
EXPORT_SYMBOL(drm_dp_read_mst_cap);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index af7ca00e9bc0..91c42949ac7e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4046,7 +4046,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
return i915->display.params.enable_dp_mst &&
intel_dp_mst_source_support(intel_dp) &&
- drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd) ==
DRM_DP_MST;
}
static void
@@ -4055,7 +4055,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
struct intel_encoder *encoder =
_to_dig_port(intel_dp)->base;
- bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd)
== DRM_DP_MST;
drm_dbg_kms(>drm,
"[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam:
%s\n",
diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c
b/drivers/gpu/drm/nouveau/nouveau_dp.c
index 7de7707ec6a8..fb06ee17d9e5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
@@ -181,7 +181,7 @@ nouveau_dp_probe_dpcd(struct nouveau_connector
*nv_connector,
if (nouveau_mst) {
mstm = outp->dp.mstm;
if (mstm)
- mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
+ mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd) ==
DRM_DP_MST;
}
if (nouveau_dp_has_sink_count(connector, outp)) {
diff --git a/include/drm/display/drm_dp_mst_helper.h
b/include/drm/display/drm_dp_mst_helper.h
index 3ae88a383a41..cbcb49cb6a46 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -817,7 +817,28 @@ int drm_dp_mst_topology_mgr_init(struct
drm_dp_mst_topology_mgr *mgr,
void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
+/**
+ * enum drm_dp_mst_mode - sink's MST mode capability
+ */
+enum drm_dp_mst_mode {
+ /**
+* @DRM_DP_SST: The sink does not support MST nor single stream sideband
+* messaging.
+*/
+ DRM_DP_SST,
+ /**
+* @DRM_DP_MST: Sink supports MST, more than one stream and single
+* stream sideband
Re: [RESEND v3 1/6] drm/mst: read sideband messaging cap
On 3/19/24 10:12, Jani Nikula wrote:
Amend drm_dp_read_mst_cap() to return an enum, indicating "SST", "SST
with sideband messaging", or "MST". Modify all call sites to take the
new return value into account.
v2:
- Rename enumerators (Ville)
Cc: Arun R Murthy
Cc: Ville Syrjälä
Cc: Karol Herbst
Cc: Lyude Paul
Cc: Danilo Krummrich
Reviewed-by: Ville Syrjälä
Signed-off-by: Jani Nikula
Acked-by: Danilo Krummrich
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 20 ++--
drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
drivers/gpu/drm/nouveau/nouveau_dp.c | 2 +-
include/drm/display/drm_dp_mst_helper.h | 23 ++-
4 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 03d528209426..c193be3577f7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -3608,24 +3608,30 @@ fixed20_12 drm_dp_get_vc_payload_bw(const struct
drm_dp_mst_topology_mgr *mgr,
EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
/**
- * drm_dp_read_mst_cap() - check whether or not a sink supports MST
+ * drm_dp_read_mst_cap() - Read the sink's MST mode capability
* @aux: The DP AUX channel to use
* @dpcd: A cached copy of the DPCD capabilities for this sink
*
- * Returns: %True if the sink supports MST, %false otherwise
+ * Returns: enum drm_dp_mst_mode to indicate MST mode capability
*/
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
-const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux,
+const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
u8 mstm_cap;
if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
- return false;
+ return DRM_DP_SST;
if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, _cap) != 1)
- return false;
+ return DRM_DP_SST;
+
+ if (mstm_cap & DP_MST_CAP)
+ return DRM_DP_MST;
+
+ if (mstm_cap & DP_SINGLE_STREAM_SIDEBAND_MSG)
+ return DRM_DP_SST_SIDEBAND_MSG;
- return mstm_cap & DP_MST_CAP;
+ return DRM_DP_SST;
}
EXPORT_SYMBOL(drm_dp_read_mst_cap);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index af7ca00e9bc0..91c42949ac7e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4046,7 +4046,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
return i915->display.params.enable_dp_mst &&
intel_dp_mst_source_support(intel_dp) &&
- drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd) ==
DRM_DP_MST;
}
static void
@@ -4055,7 +4055,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
struct intel_encoder *encoder =
_to_dig_port(intel_dp)->base;
- bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd)
== DRM_DP_MST;
drm_dbg_kms(>drm,
"[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam:
%s\n",
diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c
b/drivers/gpu/drm/nouveau/nouveau_dp.c
index 7de7707ec6a8..fb06ee17d9e5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
@@ -181,7 +181,7 @@ nouveau_dp_probe_dpcd(struct nouveau_connector
*nv_connector,
if (nouveau_mst) {
mstm = outp->dp.mstm;
if (mstm)
- mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
+ mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd) ==
DRM_DP_MST;
}
if (nouveau_dp_has_sink_count(connector, outp)) {
diff --git a/include/drm/display/drm_dp_mst_helper.h
b/include/drm/display/drm_dp_mst_helper.h
index 3ae88a383a41..cbcb49cb6a46 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -817,7 +817,28 @@ int drm_dp_mst_topology_mgr_init(struct
drm_dp_mst_topology_mgr *mgr,
void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8 dpcd[DP_RECEIVER_CAP_SIZE]);
+/**
+ * enum drm_dp_mst_mode - sink's MST mode capability
+ */
+enum drm_dp_mst_mode {
+ /**
+* @DRM_DP_SST: The sink does not support MST nor single stream sideband
+* messaging.
+*/
+ DRM_DP_SST,
+ /**
+* @DRM_DP_MST: Sink supports MST, more than one stream and single
+* stream sideband messaging.
+*/
+ DRM_DP_MST,
+ /**
+* @DRM_DP_SST_SIDEBAND_MSG: Sink supports only one stream and single
+* stream
Re: [RESEND v3 1/6] drm/mst: read sideband messaging cap
On Tue, Mar 19, 2024 at 11:20:16AM +0200, Jani Nikula wrote: > On Tue, 19 Mar 2024, Jani Nikula wrote: > > Amend drm_dp_read_mst_cap() to return an enum, indicating "SST", "SST > > with sideband messaging", or "MST". Modify all call sites to take the > > new return value into account. > > drm-misc and nouveau maintainers, ack for merging this via drm-intel, > please? Ack Maxime signature.asc Description: PGP signature
Re: [RESEND v3 1/6] drm/mst: read sideband messaging cap
On Tue, 19 Mar 2024, Jani Nikula wrote:
> Amend drm_dp_read_mst_cap() to return an enum, indicating "SST", "SST
> with sideband messaging", or "MST". Modify all call sites to take the
> new return value into account.
drm-misc and nouveau maintainers, ack for merging this via drm-intel,
please?
BR,
Jani.
>
> v2:
> - Rename enumerators (Ville)
>
> Cc: Arun R Murthy
> Cc: Ville Syrjälä
> Cc: Karol Herbst
> Cc: Lyude Paul
> Cc: Danilo Krummrich
> Reviewed-by: Ville Syrjälä
> Signed-off-by: Jani Nikula
> ---
> drivers/gpu/drm/display/drm_dp_mst_topology.c | 20 ++--
> drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
> drivers/gpu/drm/nouveau/nouveau_dp.c | 2 +-
> include/drm/display/drm_dp_mst_helper.h | 23 ++-
> 4 files changed, 38 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> index 03d528209426..c193be3577f7 100644
> --- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
> +++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
> @@ -3608,24 +3608,30 @@ fixed20_12 drm_dp_get_vc_payload_bw(const struct
> drm_dp_mst_topology_mgr *mgr,
> EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
>
> /**
> - * drm_dp_read_mst_cap() - check whether or not a sink supports MST
> + * drm_dp_read_mst_cap() - Read the sink's MST mode capability
> * @aux: The DP AUX channel to use
> * @dpcd: A cached copy of the DPCD capabilities for this sink
> *
> - * Returns: %True if the sink supports MST, %false otherwise
> + * Returns: enum drm_dp_mst_mode to indicate MST mode capability
> */
> -bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
> - const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> +enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux,
> + const u8 dpcd[DP_RECEIVER_CAP_SIZE])
> {
> u8 mstm_cap;
>
> if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
> - return false;
> + return DRM_DP_SST;
>
> if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, _cap) != 1)
> - return false;
> + return DRM_DP_SST;
> +
> + if (mstm_cap & DP_MST_CAP)
> + return DRM_DP_MST;
> +
> + if (mstm_cap & DP_SINGLE_STREAM_SIDEBAND_MSG)
> + return DRM_DP_SST_SIDEBAND_MSG;
>
> - return mstm_cap & DP_MST_CAP;
> + return DRM_DP_SST;
> }
> EXPORT_SYMBOL(drm_dp_read_mst_cap);
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index af7ca00e9bc0..91c42949ac7e 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -4046,7 +4046,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
>
> return i915->display.params.enable_dp_mst &&
> intel_dp_mst_source_support(intel_dp) &&
> - drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
> + drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd) ==
> DRM_DP_MST;
> }
>
> static void
> @@ -4055,7 +4055,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
> struct drm_i915_private *i915 = dp_to_i915(intel_dp);
> struct intel_encoder *encoder =
> _to_dig_port(intel_dp)->base;
> - bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
> + bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd)
> == DRM_DP_MST;
>
> drm_dbg_kms(>drm,
> "[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam:
> %s\n",
> diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c
> b/drivers/gpu/drm/nouveau/nouveau_dp.c
> index 7de7707ec6a8..fb06ee17d9e5 100644
> --- a/drivers/gpu/drm/nouveau/nouveau_dp.c
> +++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
> @@ -181,7 +181,7 @@ nouveau_dp_probe_dpcd(struct nouveau_connector
> *nv_connector,
> if (nouveau_mst) {
> mstm = outp->dp.mstm;
> if (mstm)
> - mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
> + mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd) ==
> DRM_DP_MST;
> }
>
> if (nouveau_dp_has_sink_count(connector, outp)) {
> diff --git a/include/drm/display/drm_dp_mst_helper.h
> b/include/drm/display/drm_dp_mst_helper.h
> index 3ae88a383a41..cbcb49cb6a46 100644
> --- a/include/drm/display/drm_dp_mst_helper.h
> +++ b/include/drm/display/drm_dp_mst_helper.h
> @@ -817,7 +817,28 @@ int drm_dp_mst_topology_mgr_init(struct
> drm_dp_mst_topology_mgr *mgr,
>
> void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
>
> -bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8
> dpcd[DP_RECEIVER_CAP_SIZE]);
> +/**
> + * enum drm_dp_mst_mode - sink's MST mode capability
> + */
> +enum drm_dp_mst_mode {
> + /**
> + * @DRM_DP_SST: The sink does not support MST nor single stream sideband
> + * messaging.
> + */
> + DRM_DP_SST,
> + /**
> + *
[RESEND v3 1/6] drm/mst: read sideband messaging cap
Amend drm_dp_read_mst_cap() to return an enum, indicating "SST", "SST
with sideband messaging", or "MST". Modify all call sites to take the
new return value into account.
v2:
- Rename enumerators (Ville)
Cc: Arun R Murthy
Cc: Ville Syrjälä
Cc: Karol Herbst
Cc: Lyude Paul
Cc: Danilo Krummrich
Reviewed-by: Ville Syrjälä
Signed-off-by: Jani Nikula
---
drivers/gpu/drm/display/drm_dp_mst_topology.c | 20 ++--
drivers/gpu/drm/i915/display/intel_dp.c | 4 ++--
drivers/gpu/drm/nouveau/nouveau_dp.c | 2 +-
include/drm/display/drm_dp_mst_helper.h | 23 ++-
4 files changed, 38 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/display/drm_dp_mst_topology.c
b/drivers/gpu/drm/display/drm_dp_mst_topology.c
index 03d528209426..c193be3577f7 100644
--- a/drivers/gpu/drm/display/drm_dp_mst_topology.c
+++ b/drivers/gpu/drm/display/drm_dp_mst_topology.c
@@ -3608,24 +3608,30 @@ fixed20_12 drm_dp_get_vc_payload_bw(const struct
drm_dp_mst_topology_mgr *mgr,
EXPORT_SYMBOL(drm_dp_get_vc_payload_bw);
/**
- * drm_dp_read_mst_cap() - check whether or not a sink supports MST
+ * drm_dp_read_mst_cap() - Read the sink's MST mode capability
* @aux: The DP AUX channel to use
* @dpcd: A cached copy of the DPCD capabilities for this sink
*
- * Returns: %True if the sink supports MST, %false otherwise
+ * Returns: enum drm_dp_mst_mode to indicate MST mode capability
*/
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux,
-const u8 dpcd[DP_RECEIVER_CAP_SIZE])
+enum drm_dp_mst_mode drm_dp_read_mst_cap(struct drm_dp_aux *aux,
+const u8 dpcd[DP_RECEIVER_CAP_SIZE])
{
u8 mstm_cap;
if (dpcd[DP_DPCD_REV] < DP_DPCD_REV_12)
- return false;
+ return DRM_DP_SST;
if (drm_dp_dpcd_readb(aux, DP_MSTM_CAP, _cap) != 1)
- return false;
+ return DRM_DP_SST;
+
+ if (mstm_cap & DP_MST_CAP)
+ return DRM_DP_MST;
+
+ if (mstm_cap & DP_SINGLE_STREAM_SIDEBAND_MSG)
+ return DRM_DP_SST_SIDEBAND_MSG;
- return mstm_cap & DP_MST_CAP;
+ return DRM_DP_SST;
}
EXPORT_SYMBOL(drm_dp_read_mst_cap);
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
b/drivers/gpu/drm/i915/display/intel_dp.c
index af7ca00e9bc0..91c42949ac7e 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -4046,7 +4046,7 @@ intel_dp_can_mst(struct intel_dp *intel_dp)
return i915->display.params.enable_dp_mst &&
intel_dp_mst_source_support(intel_dp) &&
- drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd) ==
DRM_DP_MST;
}
static void
@@ -4055,7 +4055,7 @@ intel_dp_configure_mst(struct intel_dp *intel_dp)
struct drm_i915_private *i915 = dp_to_i915(intel_dp);
struct intel_encoder *encoder =
_to_dig_port(intel_dp)->base;
- bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd);
+ bool sink_can_mst = drm_dp_read_mst_cap(_dp->aux, intel_dp->dpcd)
== DRM_DP_MST;
drm_dbg_kms(>drm,
"[ENCODER:%d:%s] MST support: port: %s, sink: %s, modparam:
%s\n",
diff --git a/drivers/gpu/drm/nouveau/nouveau_dp.c
b/drivers/gpu/drm/nouveau/nouveau_dp.c
index 7de7707ec6a8..fb06ee17d9e5 100644
--- a/drivers/gpu/drm/nouveau/nouveau_dp.c
+++ b/drivers/gpu/drm/nouveau/nouveau_dp.c
@@ -181,7 +181,7 @@ nouveau_dp_probe_dpcd(struct nouveau_connector
*nv_connector,
if (nouveau_mst) {
mstm = outp->dp.mstm;
if (mstm)
- mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
+ mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd) ==
DRM_DP_MST;
}
if (nouveau_dp_has_sink_count(connector, outp)) {
diff --git a/include/drm/display/drm_dp_mst_helper.h
b/include/drm/display/drm_dp_mst_helper.h
index 3ae88a383a41..cbcb49cb6a46 100644
--- a/include/drm/display/drm_dp_mst_helper.h
+++ b/include/drm/display/drm_dp_mst_helper.h
@@ -817,7 +817,28 @@ int drm_dp_mst_topology_mgr_init(struct
drm_dp_mst_topology_mgr *mgr,
void drm_dp_mst_topology_mgr_destroy(struct drm_dp_mst_topology_mgr *mgr);
-bool drm_dp_read_mst_cap(struct drm_dp_aux *aux, const u8
dpcd[DP_RECEIVER_CAP_SIZE]);
+/**
+ * enum drm_dp_mst_mode - sink's MST mode capability
+ */
+enum drm_dp_mst_mode {
+ /**
+* @DRM_DP_SST: The sink does not support MST nor single stream sideband
+* messaging.
+*/
+ DRM_DP_SST,
+ /**
+* @DRM_DP_MST: Sink supports MST, more than one stream and single
+* stream sideband messaging.
+*/
+ DRM_DP_MST,
+ /**
+* @DRM_DP_SST_SIDEBAND_MSG: Sink supports only one stream and single
+* stream sideband messaging.
+*/
+ DRM_DP_SST_SIDEBAND_MSG,
+};
+
+enum
