Sink's capabilities are advertised through DPCD registers and get
updated only on hotplug. So they should be computed only once in the
long pulse handler and saved off in intel_dp structure for the use
later. For this reason two new fields max_sink_lane_count and
max_sink_link_bw are added to intel_dp structure.
This also simplifies the fallback link rate/lane count logic
to handle link training failure. In that case, the max_sink_link_bw
and max_sink_lane_count can be reccomputed to match the fallback
values lowering the sink capabilities due to link train failure.
Cc: Ville Syrjala <ville.syrjala@xxxxxxxxxxxxxxx>
Cc: Jani Nikula <jani.nikula@xxxxxxxxxxxxxxx>
Cc: Daniel Vetter <daniel.vetter@xxxxxxxxx>
Signed-off-by: Manasi Navare <manasi.d.navare@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_dp.c | 10 ++++++++--
drivers/gpu/drm/i915/intel_drv.h | 4 ++++
2 files changed, 12 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index db75bb9..434dc7d 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -156,7 +156,7 @@ static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
u8 source_max, sink_max;
source_max = intel_dig_port->max_lanes;
- sink_max = drm_dp_max_lane_count(intel_dp->dpcd);
+ sink_max = intel_dp->max_sink_lane_count;
return min(source_max, sink_max);
}
@@ -213,7 +213,7 @@ static u8 intel_dp_max_lane_count(struct intel_dp *intel_dp)
*sink_rates = default_rates;
- return (intel_dp_max_link_bw(intel_dp) >> 3) + 1;
+ return (intel_dp->max_sink_link_bw >> 3) + 1;
}
static int
@@ -4395,6 +4395,12 @@ static bool intel_digital_port_connected(struct drm_i915_private *dev_priv,
yesno(intel_dp_source_supports_hbr2(intel_dp)),
yesno(drm_dp_tps3_supported(intel_dp->dpcd)));
+ /* Set the max lane count for sink */
+ intel_dp->max_sink_lane_count = drm_dp_max_lane_count(intel_dp->dpcd);
+
+ /* Set the max link BW for sink */
+ intel_dp->max_sink_link_bw = intel_dp_max_link_bw(intel_dp);
+
intel_dp_print_rates(intel_dp);
intel_dp_read_desc(intel_dp);
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index fd77a3b..b6526ad 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -906,6 +906,10 @@ struct intel_dp {
/* sink rates as reported by DP_SUPPORTED_LINK_RATES */
uint8_t num_sink_rates;
int sink_rates[DP_MAX_SUPPORTED_RATES];
+ /* Max lane count for the sink as per DPCD registers */
+ uint8_t max_sink_lane_count;
+ /* Max link BW for the sink as per DPCD registers */
+ int max_sink_link_bw;
/* sink or branch descriptor */
struct intel_dp_desc desc;
struct drm_dp_aux aux;
--
1.9.1
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