diff options
| author | Ilya Bakoulin <Ilya.Bakoulin@amd.com> | 2022-11-02 15:56:16 -0400 |
|---|---|---|
| committer | Alex Deucher <alexander.deucher@amd.com> | 2022-11-15 13:35:15 -0500 |
| commit | 180f33d27a55496e1b130ede7db24240133b2428 (patch) | |
| tree | 04f6a04257ef752a9ef8d036b1876f1500f4a486 /drivers/gpu | |
| parent | 158858bf1a96adf8370ee829060e87fd10129e62 (diff) | |
| download | linux-180f33d27a55496e1b130ede7db24240133b2428.tar.bz2 | |
drm/amd/display: Adjust DP 8b10b LT exit behavior
[Why]
Polling SINK_STATUS DPCD can cause some non-DP2.0 LTTPR hubs to hang and
no longer respond to AUX.
[How]
As a workaround for the problem hubs, and also to more closely match
DP spec 8b10b behavior, don't poll for intra-hop AUX reply indication
on 8b10b-encoded links.
Reviewed-by: Wenjing Liu <Wenjing.Liu@amd.com>
Acked-by: Tom Chung <chiahsuan.chung@amd.com>
Signed-off-by: Ilya Bakoulin <Ilya.Bakoulin@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 20 |
1 files changed, 11 insertions, 9 deletions
diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c index b772d7f2301c..dedd1246ce58 100644 --- a/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c +++ b/drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c @@ -1912,7 +1912,7 @@ enum dc_status dpcd_configure_lttpr_mode(struct dc_link *link, struct link_train return status; } -static void dpcd_exit_training_mode(struct dc_link *link) +static void dpcd_exit_training_mode(struct dc_link *link, enum dp_link_encoding encoding) { uint8_t sink_status = 0; uint8_t i; @@ -1920,12 +1920,14 @@ static void dpcd_exit_training_mode(struct dc_link *link) /* clear training pattern set */ dpcd_set_training_pattern(link, DP_TRAINING_PATTERN_VIDEOIDLE); - /* poll for intra-hop disable */ - for (i = 0; i < 10; i++) { - if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) && - (sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0) - break; - udelay(1000); + if (encoding == DP_128b_132b_ENCODING) { + /* poll for intra-hop disable */ + for (i = 0; i < 10; i++) { + if ((core_link_read_dpcd(link, DP_SINK_STATUS, &sink_status, 1) == DC_OK) && + (sink_status & DP_INTRA_HOP_AUX_REPLY_INDICATION) == 0) + break; + udelay(1000); + } } } @@ -2649,7 +2651,7 @@ enum link_training_result dc_link_dp_perform_link_training( <_settings); /* reset previous training states */ - dpcd_exit_training_mode(link); + dpcd_exit_training_mode(link, encoding); /* configure link prior to entering training mode */ dpcd_configure_lttpr_mode(link, <_settings); @@ -2670,7 +2672,7 @@ enum link_training_result dc_link_dp_perform_link_training( ASSERT(0); /* exit training mode */ - dpcd_exit_training_mode(link); + dpcd_exit_training_mode(link, encoding); /* switch to video idle */ if ((status == LINK_TRAINING_SUCCESS) || !skip_video_pattern) |