[PATCH 5.15 240/279] drm/amd/display: Limit max DSC target bpp for specific monitors

Greg Kroah-Hartman
2021-11-24T14:04:04Z

From: Roman Li <Roman.Li@amd.com>

commit 55eea8ef98641f6e1e1c202bd3a49a57c1dd4059 upstream.

[Why]
Some monitors exhibit corruption at 16bpp DSC.

[How]
- Add helpers for patching edid caps.
- Use it for limiting DSC target bitrate to 15bpp for known monitors

Reviewed-by: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>
Acked-by: Qingqing Zhuo <qingqing.zhuo@amd.com>
Signed-off-by: Roman Li <Roman.Li@amd.com>
Cc: stable@vger.kernel.org
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>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c | 35 ++++++++++++++
1 file changed, 35 insertions(+)

--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_helpers.c
@@ -40,6 +40,39 @@

#include "dm_helpers.h"

+struct monitor_patch_info {
+ unsigned int manufacturer_id;
+ unsigned int product_id;
+ void (*patch_func)(struct dc_edid_caps *edid_caps, unsigned int param);
+ unsigned int patch_param;
+};
+static void set_max_dsc_bpp_limit(struct dc_edid_caps *edid_caps, unsigned int param);
+
+static const struct monitor_patch_info monitor_patch_table[] = {
+{0x6D1E, 0x5BBF, set_max_dsc_bpp_limit, 15},
+{0x6D1E, 0x5B9A, set_max_dsc_bpp_limit, 15},
+};
+
+static void set_max_dsc_bpp_limit(struct dc_edid_caps *edid_caps, unsigned int param)
+{
+ if (edid_caps)
+ edid_caps->panel_patch.max_dsc_target_bpp_limit = param;
+}
+
+static int amdgpu_dm_patch_edid_caps(struct dc_edid_caps *edid_caps)
+{
+ int i, ret = 0;
+
+ for (i = 0; i < ARRAY_SIZE(monitor_patch_table); i++)
+ if ((edid_caps->manufacturer_id == monitor_patch_table[i].manufacturer_id)
+ && (edid_caps->product_id == monitor_patch_table[i].product_id)) {
+ monitor_patch_table[i].patch_func(edid_caps, monitor_patch_table[i].patch_param);
+ ret++;
+ }
+
+ return ret;
+}
+
/* dm_helpers_parse_edid_caps
*
* Parse edid caps
@@ -125,6 +158,8 @@ enum dc_edid_status dm_helpers_parse_edi
kfree(sads);
kfree(sadb);

+ amdgpu_dm_patch_edid_caps(edid_caps);
+
return result;
}