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drm/amd/display: Send DP_TOTAL_LTTPR_CNT during detection if LTTPR is present

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commit 2ec6c7f802332d1eff16f03e7c757f1543ee1183 upstream.

[WHY]
New register field added in DP2.1 SCR, needed for auxless ALPM

[HOW]
Echo value read from 0xF0007 back to sink

Reviewed-by: Wenjing Liu <wenjing.liu@amd.com>
Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Michael Strauss <michael.strauss@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Michael Strauss 2023-11-28 10:31:12 -05:00 committed by Greg Kroah-Hartman
parent 7ece609b0c
commit 89d8a85154
2 changed files with 14 additions and 1 deletions
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10
drivers/gpu/drm/amd/display/dc/link/protocols/link_dp_capability.c
View File

@ -1584,9 +1584,17 @@ static bool retrieve_link_cap(struct dc_link *link)
return false;
}
if (dp_is_lttpr_present(link))
if (dp_is_lttpr_present(link)) {
configure_lttpr_mode_transparent(link);
// Echo TOTAL_LTTPR_CNT back downstream
core_link_write_dpcd(
link,
DP_TOTAL_LTTPR_CNT,
&link->dpcd_caps.lttpr_caps.phy_repeater_cnt,
sizeof(link->dpcd_caps.lttpr_caps.phy_repeater_cnt));
}
/* Read DP tunneling information. */
status = dpcd_get_tunneling_device_data(link);

5
drivers/gpu/drm/amd/display/include/dpcd_defs.h
View File

@ -177,4 +177,9 @@ enum dpcd_psr_sink_states {
#define DP_SINK_PR_PIXEL_DEVIATION_PER_LINE 0x379
#define DP_SINK_PR_MAX_NUMBER_OF_DEVIATION_LINE 0x37A
/* Remove once drm_dp_helper.h is updated upstream */
#ifndef DP_TOTAL_LTTPR_CNT
#define DP_TOTAL_LTTPR_CNT 0xF000A /* 2.1 */
#endif
#endif /* __DAL_DPCD_DEFS_H__ */