HDMI2.1 PCON advertises Max FRL bandwidth supported by the PCON.
This patch captures this in dfp cap structure in intel_dp and uses
this to prune connector modes that cannot be supported by the PCON
and FRL bandwidth.
v2: Addressed review comments from Uma Shankar:
-tweaked the comparison of target bw and pcon frl bw to avoid roundup errors.
-minor modification of field names and comments.
Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@xxxxxxxxx>
Reviewed-by: Uma Shankar <uma.shankar@xxxxxxxxx>
---
.../drm/i915/display/intel_display_types.h | 1 +
drivers/gpu/drm/i915/display/intel_dp.c | 30 +++++++++++++++++--
2 files changed, 29 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
index 5bc5bfbc4551..c88d2b918d9f 100644
--- a/drivers/gpu/drm/i915/display/intel_display_types.h
+++ b/drivers/gpu/drm/i915/display/intel_display_types.h
@@ -1451,6 +1451,7 @@ struct intel_dp {
struct {
int min_tmds_clock, max_tmds_clock;
int max_dotclock;
+ int pcon_max_frl_bw;
u8 max_bpc;
bool ycbcr_444_to_420;
} dfp;
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c
index cb5e42c3ecd5..660b4bd2280a 100644
--- a/drivers/gpu/drm/i915/display/intel_dp.c
+++ b/drivers/gpu/drm/i915/display/intel_dp.c
@@ -716,6 +716,25 @@ intel_dp_mode_valid_downstream(struct intel_connector *connector,
const struct drm_display_info *info = &connector->base.display_info;
int tmds_clock;
+ /* If PCON supports FRL MODE, check FRL bandwidth constraints */
+ if (intel_dp->dfp.pcon_max_frl_bw) {
+ int target_bw;
+ int max_frl_bw;
+ int bpp = intel_dp_mode_min_output_bpp(&connector->base, mode);
+
+ target_bw = bpp * target_clock;
+
+ max_frl_bw = intel_dp->dfp.pcon_max_frl_bw;
+
+ /* converting bw from Gbps to Kbps*/
+ max_frl_bw = max_frl_bw * 1000000;
+
+ if (target_bw > max_frl_bw)
+ return MODE_CLOCK_HIGH;
+
+ return MODE_OK;
+ }
+
if (intel_dp->dfp.max_dotclock &&
target_clock > intel_dp->dfp.max_dotclock)
return MODE_CLOCK_HIGH;
@@ -6484,13 +6503,18 @@ intel_dp_update_dfp(struct intel_dp *intel_dp,
intel_dp->downstream_ports,
edid);
+ intel_dp->dfp.pcon_max_frl_bw =
+ drm_dp_get_pcon_max_frl_bw(intel_dp->dpcd,
+ intel_dp->downstream_ports);
+
drm_dbg_kms(&i915->drm,
- "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d, TMDS clock %d-%d\n",
+ "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d, TMDS clock %d-%d, PCON Max FRL BW %dGbps\n",
connector->base.base.id, connector->base.name,
intel_dp->dfp.max_bpc,
intel_dp->dfp.max_dotclock,
intel_dp->dfp.min_tmds_clock,
- intel_dp->dfp.max_tmds_clock);
+ intel_dp->dfp.max_tmds_clock,
+ intel_dp->dfp.pcon_max_frl_bw);
}
static void
@@ -6582,6 +6606,8 @@ intel_dp_unset_edid(struct intel_dp *intel_dp)
intel_dp->dfp.min_tmds_clock = 0;
intel_dp->dfp.max_tmds_clock = 0;
+ intel_dp->dfp.pcon_max_frl_bw = 0;
+
intel_dp->dfp.ycbcr_444_to_420 = false;
connector->base.ycbcr_420_allowed = false;
}
--
2.17.1
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