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drm/amd/display: Avoid reading LTTPR caps in non-LTTPR mode.

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[Why]
LTTPR capable devices on the DisplayPort path may assume that
extended LTTPR AUX timeouts will be used after LTTPR capabilities
are read.

When DPTX operates in non-LTTPR mode, AUX timeouts are not
extended and this can result in AUX transactions timing out.

[How]
Use shared helper function to determine LTTPR mode and do not
read LTTPR capabilities in non-LTTPR mode.

Reviewed-by: Mustapha Ghaddar <Mustapha.Ghaddar@amd.com>
Reviewed-by: Meenakshikumar Somasundaram <Meenakshikumar.Somasundaram@amd.com>
Reviewed-by: Jun Lei <Jun.Lei@amd.com>
Acked-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Jimmy Kizito <Jimmy.Kizito@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Jimmy Kizito 2022-03-24 13:42:45 -04:00 committed by Alex Deucher
parent 165ab7b431
commit 77361ed89a
1 changed files with 31 additions and 13 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c
View File

@ -5129,16 +5129,13 @@ static bool dpcd_read_sink_ext_caps(struct dc_link *link)
return true;
}
bool dp_retrieve_lttpr_cap(struct dc_link *link)
/* Logic to determine LTTPR mode */
static void determine_lttpr_mode(struct dc_link *link)
{
uint8_t lttpr_dpcd_data[8];
bool allow_lttpr_non_transparent_mode = 0;
bool vbios_lttpr_enable = link->dc->caps.vbios_lttpr_enable;
bool vbios_lttpr_interop = link->dc->caps.vbios_lttpr_aware;
enum dc_status status = DC_ERROR_UNEXPECTED;
bool is_lttpr_present = false;
memset(lttpr_dpcd_data, '\0', sizeof(lttpr_dpcd_data));
if ((link->dc->config.allow_lttpr_non_transparent_mode.bits.DP2_0 &&
link->dpcd_caps.channel_coding_cap.bits.DP_128b_132b_SUPPORTED)) {
@ -5148,9 +5145,6 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link)
allow_lttpr_non_transparent_mode = 1;
}
/*
* Logic to determine LTTPR mode
*/
link->lttpr_mode = LTTPR_MODE_NON_LTTPR;
if (vbios_lttpr_enable && vbios_lttpr_interop)
link->lttpr_mode = LTTPR_MODE_NON_TRANSPARENT;
@ -5172,6 +5166,18 @@ bool dp_retrieve_lttpr_cap(struct dc_link *link)
link->dc->debug.dpia_debug.bits.force_non_lttpr)
link->lttpr_mode = LTTPR_MODE_NON_LTTPR;
#endif
}
bool dp_retrieve_lttpr_cap(struct dc_link *link)
{
uint8_t lttpr_dpcd_data[8];
enum dc_status status = DC_ERROR_UNEXPECTED;
bool is_lttpr_present = false;
memset(lttpr_dpcd_data, '\0', sizeof(lttpr_dpcd_data));
/* Logic to determine LTTPR mode*/
determine_lttpr_mode(link);
if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT || link->lttpr_mode == LTTPR_MODE_TRANSPARENT) {
/* By reading LTTPR capability, RX assumes that we will enable
@ -5287,11 +5293,23 @@ static enum dc_status wa_try_to_wake_dprx(struct dc_link *link, uint64_t timeout
uint64_t time_taken_ms = 0;
enum dc_connection_type type = dc_connection_none;
status = core_link_read_dpcd(
link,
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
&dpcd_data,
sizeof(dpcd_data));
determine_lttpr_mode(link);
/* Issue an AUX read to test DPRX responsiveness. If LTTPR is supported the first read is expected to
* be to determine LTTPR capabilities. Otherwise trying to read power state should be an innocuous AUX read.
*/
if (link->lttpr_mode == LTTPR_MODE_NON_TRANSPARENT || link->lttpr_mode == LTTPR_MODE_TRANSPARENT)
status = core_link_read_dpcd(
link,
DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
&dpcd_data,
sizeof(dpcd_data));
else
status = core_link_read_dpcd(
link,
DP_SET_POWER,
&dpcd_data,
sizeof(dpcd_data));
if (status != DC_OK) {
DC_LOG_WARNING("%s: Read DPCD LTTPR_CAP failed - try to toggle DPCD SET_POWER for %lld ms.",