drm/amd/display: restore edid reading from a given i2c adapter

When switching to drm_edid, we slightly changed how to get edid by
removing the possibility of getting them from dc_link when in aux
transaction mode. As MST doesn't initialize the connector with
`drm_connector_init_with_ddc()`, restore the original behavior to avoid
functional changes.

v2:
- Fix build warning of unchecked dereference (kernel test bot)

CC: Alex Hung <alex.hung@amd.com>
CC: Mario Limonciello <mario.limonciello@amd.com>
CC: Roman Li <Roman.Li@amd.com>
CC: Aurabindo Pillai <Aurabindo.Pillai@amd.com>
Fixes: 48edb2a4256e ("drm/amd/display: switch amdgpu_dm_connector to use struct drm_edid")
Reviewed-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Melissa Wen <mwen@igalia.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 009e2696f2c8df77c09c2273f575261bca2f3655..e3df652bb74e9fb1d9fc31e35048e25c04e8182e 100644 (file)
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -7295,8 +7295,14 @@ static void amdgpu_dm_connector_funcs_force(struct drm_connector *connector)
        struct dc_link *dc_link = aconnector->dc_link;
        struct dc_sink *dc_em_sink = aconnector->dc_em_sink;
        const struct drm_edid *drm_edid;
+       struct i2c_adapter *ddc;
 
-       drm_edid = drm_edid_read(connector);
+       if (dc_link && dc_link->aux_mode)
+               ddc = &aconnector->dm_dp_aux.aux.ddc;
+       else
+               ddc = &aconnector->i2c->base;
+
+       drm_edid = drm_edid_read_ddc(connector, ddc);
        drm_edid_connector_update(connector, drm_edid);
        if (!drm_edid) {
                DRM_ERROR("No EDID found on connector: %s.\n", connector->name);
@@ -7341,14 +7347,21 @@ static int get_modes(struct drm_connector *connector)
 static void create_eml_sink(struct amdgpu_dm_connector *aconnector)
 {
        struct drm_connector *connector = &aconnector->base;
+       struct dc_link *dc_link = aconnector->dc_link;
        struct dc_sink_init_data init_params = {
                        .link = aconnector->dc_link,
                        .sink_signal = SIGNAL_TYPE_VIRTUAL
        };
        const struct drm_edid *drm_edid;
        const struct edid *edid;
+       struct i2c_adapter *ddc;
+
+       if (dc_link && dc_link->aux_mode)
+               ddc = &aconnector->dm_dp_aux.aux.ddc;
+       else
+               ddc = &aconnector->i2c->base;
 
-       drm_edid = drm_edid_read(connector);
+       drm_edid = drm_edid_read_ddc(connector, ddc);
        drm_edid_connector_update(connector, drm_edid);
        if (!drm_edid) {
                DRM_ERROR("No EDID found on connector: %s.\n", connector->name);