From: Ian Chen <ian.chen@amd.com>

Date: Mon, 28 Nov 2022 16:17:34 +0800

Subject: [PATCH] drm/amd/display: Revert Reduce delay when sink device not

 able to ACK 00340h write

References: bsc#1012628

Patch-mainline: 6.2.3

Git-commit: 639f6ad6df7f47db48b59956b469a6917a136afb

[ Upstream commit 639f6ad6df7f47db48b59956b469a6917a136afb ]

[WHY]

It causes regression AMD source will not write DPCD 340.

Reviewed-by: Wayne Lin <Wayne.Lin@amd.com>

Acked-by: Jasdeep Dhillon <jdhillon@amd.com>

Signed-off-by: Ian Chen <ian.chen@amd.com>

Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

Signed-off-by: Sasha Levin <sashal@kernel.org>

Signed-off-by: Jiri Slaby <jslaby@suse.cz>

---

 drivers/gpu/drm/amd/display/dc/core/dc_link.c    |  6 ------

 drivers/gpu/drm/amd/display/dc/core/dc_link_dp.c | 14 +++-----------

 drivers/gpu/drm/amd/display/dc/dc_dp_types.h     |  1 -

 3 files changed, 3 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/display/dc/core/dc_link.c b/drivers/gpu/drm/amd/display/dc/core/dc_link.c

index c88f0446..754fc863 100644

--- a/drivers/gpu/drm/amd/display/dc/core/dc_link.c

+++ b/drivers/gpu/drm/amd/display/dc/core/dc_link.c

@@ -1916,12 +1916,6 @@ struct dc_link *link_create(const struct link_init_data *init_params)

 	if (false == dc_link_construct(link, init_params))

 		goto construct_fail;

-	/*

-	 * Must use preferred_link_setting, not reported_link_cap or verified_link_cap,

-	 * since struct preferred_link_setting won't be reset after S3.

-	 */

-	link->preferred_link_setting.dpcd_source_device_specific_field_support = true;

-

 	return link;

 construct_fail:

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 dedd1246..475ad3ee 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

@@ -6554,18 +6554,10 @@ void dpcd_set_source_specific_data(struct dc_link *link)

 			uint8_t hblank_size = (uint8_t)link->dc->caps.min_horizontal_blanking_period;

-			if (link->preferred_link_setting.dpcd_source_device_specific_field_support) {

-				result_write_min_hblank = core_link_write_dpcd(link,

-					DP_SOURCE_MINIMUM_HBLANK_SUPPORTED, (uint8_t *)(&hblank_size),

-					sizeof(hblank_size));

-

-				if (result_write_min_hblank == DC_ERROR_UNEXPECTED)

-					link->preferred_link_setting.dpcd_source_device_specific_field_support = false;

-			} else {

-				DC_LOG_DC("Sink device does not support 00340h DPCD write. Skipping on purpose.\n");

-			}

+			result_write_min_hblank = core_link_write_dpcd(link,

+				DP_SOURCE_MINIMUM_HBLANK_SUPPORTED, (uint8_t *)(&hblank_size),

+				sizeof(hblank_size));

 		}

-

 		DC_TRACE_LEVEL_MESSAGE(DAL_TRACE_LEVEL_INFORMATION,

 							WPP_BIT_FLAG_DC_DETECTION_DP_CAPS,

 							"result=%u link_index=%u enum dce_version=%d DPCD=0x%04X min_hblank=%u branch_dev_id=0x%x branch_dev_name='%c%c%c%c%c%c'",

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h

index 2c54b6e0..296793d8 100644

--- a/drivers/gpu/drm/amd/display/dc/dc_dp_types.h

+++ b/drivers/gpu/drm/amd/display/dc/dc_dp_types.h

@@ -149,7 +149,6 @@ struct dc_link_settings {

 	enum dc_link_spread link_spread;

 	bool use_link_rate_set;

 	uint8_t link_rate_set;

-	bool dpcd_source_device_specific_field_support;

 };

 union dc_dp_ffe_preset {

-- 

2.35.3