[PATCH 2/2] drm/radeon: fix dp link rate selection
Alex Deucher
alexdeucher at gmail.com
Thu Dec 17 08:23:26 PST 2015
Need to properly handle the max link rate in the dpcd.
This prevents some cases where 5.4 Ghz is selected when
it shouldn't be.
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
drivers/gpu/drm/radeon/atombios_dp.c | 110 ++++++++++++---------------------
drivers/gpu/drm/radeon/radeon_dp_mst.c | 12 +++-
drivers/gpu/drm/radeon/radeon_mode.h | 6 +-
3 files changed, 51 insertions(+), 77 deletions(-)
diff --git a/drivers/gpu/drm/radeon/atombios_dp.c b/drivers/gpu/drm/radeon/atombios_dp.c
index bd73b40..6ef2233 100644
--- a/drivers/gpu/drm/radeon/atombios_dp.c
+++ b/drivers/gpu/drm/radeon/atombios_dp.c
@@ -302,77 +302,33 @@ static int convert_bpc_to_bpp(int bpc)
return bpc * 3;
}
-/* get the max pix clock supported by the link rate and lane num */
-static int dp_get_max_dp_pix_clock(int link_rate,
- int lane_num,
- int bpp)
-{
- return (link_rate * lane_num * 8) / bpp;
-}
-
/***** radeon specific DP functions *****/
-int radeon_dp_get_max_link_rate(struct drm_connector *connector,
- const u8 dpcd[DP_DPCD_SIZE])
-{
- int max_link_rate;
-
- if (radeon_connector_is_dp12_capable(connector))
- max_link_rate = min(drm_dp_max_link_rate(dpcd), 540000);
- else
- max_link_rate = min(drm_dp_max_link_rate(dpcd), 270000);
-
- return max_link_rate;
-}
-
-/* First get the min lane# when low rate is used according to pixel clock
- * (prefer low rate), second check max lane# supported by DP panel,
- * if the max lane# < low rate lane# then use max lane# instead.
- */
-static int radeon_dp_get_dp_lane_number(struct drm_connector *connector,
- const u8 dpcd[DP_DPCD_SIZE],
- int pix_clock)
-{
- int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
- int max_link_rate = radeon_dp_get_max_link_rate(connector, dpcd);
- int max_lane_num = drm_dp_max_lane_count(dpcd);
- int lane_num;
- int max_dp_pix_clock;
-
- for (lane_num = 1; lane_num < max_lane_num; lane_num <<= 1) {
- max_dp_pix_clock = dp_get_max_dp_pix_clock(max_link_rate, lane_num, bpp);
- if (pix_clock <= max_dp_pix_clock)
- break;
- }
-
- return lane_num;
-}
-
-static int radeon_dp_get_dp_link_clock(struct drm_connector *connector,
- const u8 dpcd[DP_DPCD_SIZE],
- int pix_clock)
+int radeon_dp_get_dp_link_config(struct drm_connector *connector,
+ const u8 dpcd[DP_DPCD_SIZE],
+ unsigned pix_clock,
+ unsigned *dp_lanes, unsigned *dp_rate)
{
int bpp = convert_bpc_to_bpp(radeon_get_monitor_bpc(connector));
- int lane_num, max_pix_clock;
-
- if (radeon_connector_encoder_get_dp_bridge_encoder_id(connector) ==
- ENCODER_OBJECT_ID_NUTMEG)
- return 270000;
-
- lane_num = radeon_dp_get_dp_lane_number(connector, dpcd, pix_clock);
- max_pix_clock = dp_get_max_dp_pix_clock(162000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 162000;
- max_pix_clock = dp_get_max_dp_pix_clock(270000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 270000;
- if (radeon_connector_is_dp12_capable(connector)) {
- max_pix_clock = dp_get_max_dp_pix_clock(540000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 540000;
+ static const unsigned link_rates[3] = { 162000, 270000, 540000 };
+ unsigned max_link_rate = drm_dp_max_link_rate(dpcd);
+ unsigned max_lane_num = drm_dp_max_lane_count(dpcd);
+ unsigned long req_bw = pix_clock * bpp;
+ unsigned long avail_bw;
+ unsigned lane_num, i;
+
+ for (lane_num = 1; lane_num <= max_lane_num; lane_num <<= 1) {
+ for (i = 0; link_rates[i] <= max_link_rate; i++) {
+ avail_bw = lane_num * link_rates[i] * 8;
+ if (avail_bw >= req_bw) {
+ *dp_lanes = lane_num;
+ *dp_rate = link_rates[i];
+ return 0;
+ }
+ }
}
- return radeon_dp_get_max_link_rate(connector, dpcd);
+ return -EINVAL;
}
static u8 radeon_dp_encoder_service(struct radeon_device *rdev,
@@ -491,6 +447,7 @@ void radeon_dp_set_link_config(struct drm_connector *connector,
{
struct radeon_connector *radeon_connector = to_radeon_connector(connector);
struct radeon_connector_atom_dig *dig_connector;
+ int ret;
if (!radeon_connector->con_priv)
return;
@@ -498,10 +455,14 @@ void radeon_dp_set_link_config(struct drm_connector *connector,
if ((dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_DISPLAYPORT) ||
(dig_connector->dp_sink_type == CONNECTOR_OBJECT_ID_eDP)) {
- dig_connector->dp_clock =
- radeon_dp_get_dp_link_clock(connector, dig_connector->dpcd, mode->clock);
- dig_connector->dp_lane_count =
- radeon_dp_get_dp_lane_number(connector, dig_connector->dpcd, mode->clock);
+ ret = radeon_dp_get_dp_link_config(connector, dig_connector->dpcd,
+ mode->clock,
+ &dig_connector->dp_lane_count,
+ &dig_connector->dp_clock);
+ if (ret) {
+ dig_connector->dp_clock = 0;
+ dig_connector->dp_lane_count = 0;
+ }
}
}
@@ -510,7 +471,8 @@ int radeon_dp_mode_valid_helper(struct drm_connector *connector,
{
struct radeon_connector *radeon_connector = to_radeon_connector(connector);
struct radeon_connector_atom_dig *dig_connector;
- int dp_clock;
+ unsigned dp_clock, dp_lanes;
+ int ret;
if ((mode->clock > 340000) &&
(!radeon_connector_is_dp12_capable(connector)))
@@ -520,8 +482,12 @@ int radeon_dp_mode_valid_helper(struct drm_connector *connector,
return MODE_CLOCK_HIGH;
dig_connector = radeon_connector->con_priv;
- dp_clock =
- radeon_dp_get_dp_link_clock(connector, dig_connector->dpcd, mode->clock);
+ ret = radeon_dp_get_dp_link_config(connector, dig_connector->dpcd,
+ mode->clock,
+ &dp_lanes,
+ &dp_clock);
+ if (ret)
+ return MODE_CLOCK_HIGH;
if ((dp_clock == 540000) &&
(!radeon_connector_is_dp12_capable(connector)))
diff --git a/drivers/gpu/drm/radeon/radeon_dp_mst.c b/drivers/gpu/drm/radeon/radeon_dp_mst.c
index 744f5c4..b431c9c 100644
--- a/drivers/gpu/drm/radeon/radeon_dp_mst.c
+++ b/drivers/gpu/drm/radeon/radeon_dp_mst.c
@@ -525,11 +525,17 @@ static bool radeon_mst_mode_fixup(struct drm_encoder *encoder,
drm_mode_set_crtcinfo(adjusted_mode, 0);
{
struct radeon_connector_atom_dig *dig_connector;
+ int ret;
dig_connector = mst_enc->connector->con_priv;
- dig_connector->dp_lane_count = drm_dp_max_lane_count(dig_connector->dpcd);
- dig_connector->dp_clock = radeon_dp_get_max_link_rate(&mst_enc->connector->base,
- dig_connector->dpcd);
+ ret = radeon_dp_get_dp_link_config(&mst_enc->connector->base,
+ dig_connector->dpcd, adjusted_mode->clock,
+ &dig_connector->dp_lane_count,
+ &dig_connector->dp_clock);
+ if (ret) {
+ dig_connector->dp_lane_count = 0;
+ dig_connector->dp_clock = 0;
+ }
DRM_DEBUG_KMS("dig clock %p %d %d\n", dig_connector,
dig_connector->dp_lane_count, dig_connector->dp_clock);
}
diff --git a/drivers/gpu/drm/radeon/radeon_mode.h b/drivers/gpu/drm/radeon/radeon_mode.h
index bba1126..7a0666a 100644
--- a/drivers/gpu/drm/radeon/radeon_mode.h
+++ b/drivers/gpu/drm/radeon/radeon_mode.h
@@ -757,8 +757,10 @@ extern u8 radeon_dp_getsinktype(struct radeon_connector *radeon_connector);
extern bool radeon_dp_getdpcd(struct radeon_connector *radeon_connector);
extern int radeon_dp_get_panel_mode(struct drm_encoder *encoder,
struct drm_connector *connector);
-int radeon_dp_get_max_link_rate(struct drm_connector *connector,
- const u8 *dpcd);
+extern int radeon_dp_get_dp_link_config(struct drm_connector *connector,
+ const u8 *dpcd,
+ unsigned pix_clock,
+ unsigned *dp_lanes, unsigned *dp_rate);
extern void radeon_dp_set_rx_power_state(struct drm_connector *connector,
u8 power_state);
extern void radeon_dp_aux_init(struct radeon_connector *radeon_connector);
--
2.5.0
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