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.
v2: simplify logic, add array bounds check
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/atombios_dp.c | 96 ++++++++++++--------------------
1 file changed, 36 insertions(+), 60 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
index 92b6aca..21aacc1 100644
--- a/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
+++ b/drivers/gpu/drm/amd/amdgpu/atombios_dp.c
@@ -243,7 +243,7 @@ static void amdgpu_atombios_dp_get_adjust_train(const u8 link_status[DP_LINK_STA
/* convert bits per color to bits per pixel */
/* get bpc from the EDID */
-static int amdgpu_atombios_dp_convert_bpc_to_bpp(int bpc)
+static unsigned amdgpu_atombios_dp_convert_bpc_to_bpp(int bpc)
{
if (bpc == 0)
return 24;
@@ -251,64 +251,32 @@ static int amdgpu_atombios_dp_convert_bpc_to_bpp(int bpc)
return bpc * 3;
}
-/* get the max pix clock supported by the link rate and lane num */
-static int amdgpu_atombios_dp_get_max_dp_pix_clock(int link_rate,
- int lane_num,
- int bpp)
-{
- return (link_rate * lane_num * 8) / bpp;
-}
-
/***** amdgpu specific DP functions *****/
-/* 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 amdgpu_atombios_dp_get_dp_lane_number(struct drm_connector *connector,
+static int amdgpu_atombios_dp_get_dp_link_config(struct drm_connector *connector,
const u8 dpcd[DP_DPCD_SIZE],
- int pix_clock)
-{
- int bpp = amdgpu_atombios_dp_convert_bpc_to_bpp(amdgpu_connector_get_monitor_bpc(connector));
- int max_link_rate = drm_dp_max_link_rate(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 = amdgpu_atombios_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 amdgpu_atombios_dp_get_dp_link_clock(struct drm_connector *connector,
- const u8 dpcd[DP_DPCD_SIZE],
- int pix_clock)
+ unsigned pix_clock,
+ unsigned *dp_lanes, unsigned *dp_rate)
{
- int bpp = amdgpu_atombios_dp_convert_bpc_to_bpp(amdgpu_connector_get_monitor_bpc(connector));
- int lane_num, max_pix_clock;
-
- if (amdgpu_connector_encoder_get_dp_bridge_encoder_id(connector) ==
- ENCODER_OBJECT_ID_NUTMEG)
- return 270000;
-
- lane_num = amdgpu_atombios_dp_get_dp_lane_number(connector, dpcd, pix_clock);
- max_pix_clock = amdgpu_atombios_dp_get_max_dp_pix_clock(162000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 162000;
- max_pix_clock = amdgpu_atombios_dp_get_max_dp_pix_clock(270000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 270000;
- if (amdgpu_connector_is_dp12_capable(connector)) {
- max_pix_clock = amdgpu_atombios_dp_get_max_dp_pix_clock(540000, lane_num, bpp);
- if (pix_clock <= max_pix_clock)
- return 540000;
+ unsigned bpp =
+ amdgpu_atombios_dp_convert_bpc_to_bpp(amdgpu_connector_get_monitor_bpc(connector));
+ 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 lane_num, i, max_pix_clock;
+
+ for (lane_num = 1; lane_num <= max_lane_num; lane_num <<= 1) {
+ for (i = 0; i < ARRAY_SIZE(link_rates) && link_rates[i] <= max_link_rate; i++) {
+ max_pix_clock = (lane_num * link_rates[i] * 8) / bpp;
+ if (max_pix_clock >= pix_clock) {
+ *dp_lanes = lane_num;
+ *dp_rate = link_rates[i];
+ return 0;
+ }
+ }
}
- return drm_dp_max_link_rate(dpcd);
+ return -EINVAL;
}
static u8 amdgpu_atombios_dp_encoder_service(struct amdgpu_device *adev,
@@ -422,6 +390,7 @@ void amdgpu_atombios_dp_set_link_config(struct drm_connector *connector,
{
struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
struct amdgpu_connector_atom_dig *dig_connector;
+ int ret;
if (!amdgpu_connector->con_priv)
return;
@@ -429,10 +398,14 @@ void amdgpu_atombios_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 =
- amdgpu_atombios_dp_get_dp_link_clock(connector, dig_connector->dpcd, mode->clock);
- dig_connector->dp_lane_count =
- amdgpu_atombios_dp_get_dp_lane_number(connector, dig_connector->dpcd, mode->clock);
+ ret = amdgpu_atombios_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;
+ }
}
}
@@ -441,14 +414,17 @@ int amdgpu_atombios_dp_mode_valid_helper(struct drm_connector *connector,
{
struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
struct amdgpu_connector_atom_dig *dig_connector;
- int dp_clock;
+ unsigned dp_lanes, dp_clock;
+ int ret;
if (!amdgpu_connector->con_priv)
return MODE_CLOCK_HIGH;
dig_connector = amdgpu_connector->con_priv;
- dp_clock =
- amdgpu_atombios_dp_get_dp_link_clock(connector, dig_connector->dpcd, mode->clock);
+ ret = amdgpu_atombios_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) &&
(!amdgpu_connector_is_dp12_capable(connector)))
--
2.5.0
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