When testing, it's convenient to be able to ignore DPCD errors if there
is test equipment which can't emulate a DPRX connected to the output.
Add some (currently-unused) options to ignore these errors and just
reconfigure our internal registers as we usually would.
Signed-off-by: Sean Anderson <sean.ander...@linux.dev>
---
drivers/gpu/drm/xlnx/zynqmp_dp.c | 37 ++++++++++++++++++++------------
1 file changed, 23 insertions(+), 14 deletions(-)
diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 24043847dab4..040f7b88ee51 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -628,6 +628,7 @@ static void zynqmp_dp_adjust_train(struct zynqmp_dp *dp,
* zynqmp_dp_update_vs_emph - Update the training values
* @dp: DisplayPort IP core structure
* @train_set: A set of training values
+ * @ignore_dpcd: Ignore DPCD errors
*
* Update the training values based on the request from sink. The mapped values
* are predefined, and values(vs, pe, pc) are from the device manual.
@@ -635,15 +636,19 @@ static void zynqmp_dp_adjust_train(struct zynqmp_dp *dp,
* Return: 0 if vs and emph are updated successfully, or the error code
returned
* by drm_dp_dpcd_write().
*/
-static int zynqmp_dp_update_vs_emph(struct zynqmp_dp *dp, u8 *train_set)
+static int zynqmp_dp_update_vs_emph(struct zynqmp_dp *dp, u8 *train_set,
+ bool ignore_dpcd)
{
unsigned int i;
int ret;
ret = drm_dp_dpcd_write(&dp->aux, DP_TRAINING_LANE0_SET, train_set,
dp->mode.lane_cnt);
- if (ret < 0)
- return ret;
+ if (ret < 0) {
+ if (!ignore_dpcd)
+ return ret;
+ dev_warn(dp->dev, "failed to update vs/emph\n");
+ }
for (i = 0; i < dp->mode.lane_cnt; i++) {
u32 reg = ZYNQMP_DP_SUB_TX_PHY_PRECURSOR_LANE_0 + i * 4;
@@ -692,7 +697,7 @@ static int zynqmp_dp_link_train_cr(struct zynqmp_dp *dp)
* So, This loop should exit before 512 iterations
*/
for (max_tries = 0; max_tries < 512; max_tries++) {
- ret = zynqmp_dp_update_vs_emph(dp, dp->train_set);
+ ret = zynqmp_dp_update_vs_emph(dp, dp->train_set, false);
if (ret)
return ret;
@@ -757,7 +762,7 @@ static int zynqmp_dp_link_train_ce(struct zynqmp_dp *dp)
return ret;
for (tries = 0; tries < DP_MAX_TRAINING_TRIES; tries++) {
- ret = zynqmp_dp_update_vs_emph(dp, dp->train_set);
+ ret = zynqmp_dp_update_vs_emph(dp, dp->train_set, false);
if (ret)
return ret;
@@ -785,11 +790,12 @@ static int zynqmp_dp_link_train_ce(struct zynqmp_dp *dp)
* @lane_cnt: The number of lanes to use
* @enhanced: Use enhanced framing
* @downspread: Enable spread-spectrum clocking
+ * @ignore_dpcd: Ignore DPCD errors; useful for testing
*
* Return: 0 on success, or -errno on failure
*/
static int zynqmp_dp_setup(struct zynqmp_dp *dp, u8 bw_code, u8 lane_cnt,
- bool enhanced, bool downspread)
+ bool enhanced, bool downspread, bool ignore_dpcd)
{
u32 reg;
u8 aux_lane_cnt = lane_cnt;
@@ -812,21 +818,24 @@ static int zynqmp_dp_setup(struct zynqmp_dp *dp, u8
bw_code, u8 lane_cnt,
ret = drm_dp_dpcd_writeb(&dp->aux, DP_LANE_COUNT_SET, aux_lane_cnt);
if (ret < 0) {
- dev_err(dp->dev, "failed to set lane count\n");
- return ret;
+ dev_warn(dp->dev, "failed to set lane count\n");
+ if (!ignore_dpcd)
+ return ret;
}
ret = drm_dp_dpcd_writeb(&dp->aux, DP_MAIN_LINK_CHANNEL_CODING_SET,
DP_SET_ANSI_8B10B);
if (ret < 0) {
- dev_err(dp->dev, "failed to set ANSI 8B/10B encoding\n");
- return ret;
+ dev_warn(dp->dev, "failed to set ANSI 8B/10B encoding\n");
+ if (!ignore_dpcd)
+ return ret;
}
ret = drm_dp_dpcd_writeb(&dp->aux, DP_LINK_BW_SET, bw_code);
if (ret < 0) {
- dev_err(dp->dev, "failed to set DP bandwidth\n");
- return ret;
+ dev_warn(dp->dev, "failed to set DP bandwidth\n");
+ if (!ignore_dpcd)
+ return ret;
}
zynqmp_dp_write(dp, ZYNQMP_DP_LINK_BW_SET, bw_code);
@@ -860,7 +869,7 @@ static int zynqmp_dp_train(struct zynqmp_dp *dp)
ret = zynqmp_dp_setup(dp, dp->mode.bw_code, dp->mode.lane_cnt,
drm_dp_enhanced_frame_cap(dp->dpcd),
- dp->dpcd[3] & 0x1);
+ dp->dpcd[3] & 0x1, false);
if (ret)
return ret;
@@ -877,7 +886,7 @@ static int zynqmp_dp_train(struct zynqmp_dp *dp)
ret = drm_dp_dpcd_writeb(&dp->aux, DP_TRAINING_PATTERN_SET,
DP_TRAINING_PATTERN_DISABLE);
if (ret < 0) {
- dev_err(dp->dev, "failed to disable training pattern\n");
+ dev_warn(dp->dev, "failed to disable training pattern\n");
return ret;
}
zynqmp_dp_write(dp, ZYNQMP_DP_TRAINING_PATTERN_SET,
--
2.35.1.1320.gc452695387.dirty
