From f4f3b7dedbe849e780c779ba67365bb1db0d8637 Mon Sep 17 00:00:00 2001 From: Fangzhi Zuo Date: Fri, 24 Feb 2023 13:45:21 -0500 Subject: [PATCH] drm/amd/display: Add DSC Support for Synaptics Cascaded MST Hub Traditional synaptics hub has one MST branch device without virtual dpcd. Synaptics cascaded hub has two chained MST branch devices. DSC decoding is performed via root MST branch device, instead of the second MST branch device. Reviewed-by: Hersen Wu Acked-by: Qingqing Zhuo Signed-off-by: Fangzhi Zuo Tested-by: Daniel Wheeler Signed-off-by: Alex Deucher Cc: stable@vger.kernel.org --- .../drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c | 19 +++++++++++++++++++ .../drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h | 12 ++++++++++++ 2 files changed, 31 insertions(+) diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c index e25e1b2..30de0aa 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c @@ -212,6 +212,21 @@ bool needs_dsc_aux_workaround(struct dc_link *link) return false; } +bool is_synaptics_cascaded_panamera(struct dc_link *link, struct drm_dp_mst_port *port) +{ + u8 branch_vendor_data[4] = { 0 }; // Vendor data 0x50C ~ 0x50F + + if (drm_dp_dpcd_read(port->mgr->aux, DP_BRANCH_VENDOR_SPECIFIC_START, &branch_vendor_data, 4) == 4) { + if (link->dpcd_caps.branch_dev_id == DP_BRANCH_DEVICE_ID_90CC24 && + IS_SYNAPTICS_CASCADED_PANAMERA(link->dpcd_caps.branch_dev_name, branch_vendor_data)) { + DRM_INFO("Synaptics Cascaded MST hub\n"); + return true; + } + } + + return false; +} + static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnector) { struct dc_sink *dc_sink = aconnector->dc_sink; @@ -235,6 +250,10 @@ static bool validate_dsc_caps_on_connector(struct amdgpu_dm_connector *aconnecto needs_dsc_aux_workaround(aconnector->dc_link)) aconnector->dsc_aux = &aconnector->mst_root->dm_dp_aux.aux; + /* synaptics cascaded MST hub case */ + if (!aconnector->dsc_aux && is_synaptics_cascaded_panamera(aconnector->dc_link, port)) + aconnector->dsc_aux = port->mgr->aux; + if (!aconnector->dsc_aux) return false; diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h index 97fd70d..0b57502 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.h @@ -34,6 +34,18 @@ #define SYNAPTICS_RC_OFFSET 0x4BC #define SYNAPTICS_RC_DATA 0x4C0 +#define DP_BRANCH_VENDOR_SPECIFIC_START 0x50C + +/** + * Panamera MST Hub detection + * Offset DPCD 050Eh == 0x5A indicates cascaded MST hub case + * Check from beginning of branch device vendor specific field (050Ch) + */ +#define IS_SYNAPTICS_PANAMERA(branchDevName) (((int)branchDevName[4] & 0xF0) == 0x50 ? 1 : 0) +#define BRANCH_HW_REVISION_PANAMERA_A2 0x10 +#define SYNAPTICS_CASCADED_HUB_ID 0x5A +#define IS_SYNAPTICS_CASCADED_PANAMERA(devName, data) ((IS_SYNAPTICS_PANAMERA(devName) && ((int)data[2] == SYNAPTICS_CASCADED_HUB_ID)) ? 1 : 0) + struct amdgpu_display_manager; struct amdgpu_dm_connector; -- 2.7.4