* [PATCH 0/2] drm: detect panel type from DisplayID 2.x @ 2026-05-14 6:54 Chenyu Chen 2026-05-14 6:54 ` [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block Chenyu Chen 2026-05-14 6:54 ` [PATCH 2/2] drm/amd/display: use DisplayID panel type in dm_set_panel_type Chenyu Chen 0 siblings, 2 replies; 4+ messages in thread From: Chenyu Chen @ 2026-05-14 6:54 UTC (permalink / raw) To: amd-gfx, dri-devel Cc: Harry Wentland, Leo Li, Ray Wu, Limonciello Mario, Jani Nikula, Chenyu Chen Parse the Display Device Technology field from the DisplayID v2.x Display Parameters Data Block to identify LCD and OLED panels, and wire it into amdgpu_dm as a fallback for panel type detection. Chenyu Chen (2): drm/edid: parse panel type from DisplayID 2.x Display Parameters block drm/amd/display: use DisplayID panel type in dm_set_panel_type .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 ++-- drivers/gpu/drm/drm_displayid_internal.h | 25 ++++++++ drivers/gpu/drm/drm_edid.c | 61 +++++++++++++++---- include/drm/drm_connector.h | 6 ++ include/uapi/drm/drm_mode.h | 1 + 5 files changed, 89 insertions(+), 16 deletions(-) -- 2.43.0 ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block 2026-05-14 6:54 [PATCH 0/2] drm: detect panel type from DisplayID 2.x Chenyu Chen @ 2026-05-14 6:54 ` Chenyu Chen 2026-05-15 8:23 ` Jani Nikula 2026-05-14 6:54 ` [PATCH 2/2] drm/amd/display: use DisplayID panel type in dm_set_panel_type Chenyu Chen 1 sibling, 1 reply; 4+ messages in thread From: Chenyu Chen @ 2026-05-14 6:54 UTC (permalink / raw) To: amd-gfx, dri-devel Cc: Harry Wentland, Leo Li, Ray Wu, Limonciello Mario, Jani Nikula, Chenyu Chen, Mario Limonciello Parse the Display Parameters Data Block (tag 0x21) defined in DisplayID v2.1a Section 4.2.6. Extract the Display Device Technology field from payload byte 27, bits [6:4], which indicates whether the panel is LCD (001b) or OLED (010b). Store the result in drm_display_info.did_panel_type so that downstream drivers can use it for panel-type-dependent behavior. Assisted-by: Copilot:Claude-Opus-4.6 Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> --- drivers/gpu/drm/drm_displayid_internal.h | 25 ++++++++++ drivers/gpu/drm/drm_edid.c | 61 +++++++++++++++++++----- include/drm/drm_connector.h | 6 +++ include/uapi/drm/drm_mode.h | 1 + 4 files changed, 82 insertions(+), 11 deletions(-) diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h index 5b1b32f73516..e0f7c54d2987 100644 --- a/drivers/gpu/drm/drm_displayid_internal.h +++ b/drivers/gpu/drm/drm_displayid_internal.h @@ -142,6 +142,31 @@ struct displayid_formula_timing_block { struct displayid_formula_timings_9 timings[]; } __packed; +/* + * DisplayID v2.x Display Parameters Data Block (tag 0x21). + * + * Per VESA DisplayID v2.1a, Section 4.2.6, Table 4-14: + * Offset 0x1E (payload byte 27) contains Native Color Depth and + * Display Device Technology fields. + * bits [2:0] = Native Color Depth + * bit [3] = RESERVED + * bits [6:4] = Display Device Technology + * 000b = not specified, 001b = LCD, 010b = OLED, others reserved + * bit [7] = Display Device Theme Preference + */ +#define DISPLAYID_DISPLAY_PARAMS_DEVICE_TECH GENMASK(6, 4) + +struct displayid_display_params_block { + struct displayid_block base; + u8 payload[27]; + u8 device_tech_byte; /* bits [6:4] = Display Device Technology */ + u8 reserved; +} __packed; + +#define DISPLAYID_DISPLAY_PARAMS_MIN_LEN \ + (sizeof(struct displayid_display_params_block) - \ + sizeof(struct displayid_block)) + #define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0) #define DISPLAYID_VESA_MSO_MODE GENMASK(6, 5) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 8031f021d4d0..9b160a878df4 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -6713,6 +6713,8 @@ static void drm_reset_display_info(struct drm_connector *connector) info->source_physical_address = CEC_PHYS_ADDR_INVALID; memset(&info->amd_vsdb, 0, sizeof(info->amd_vsdb)); + + info->did_panel_type = DRM_MODE_PANEL_TYPE_UNKNOWN; } static void update_displayid_info(struct drm_connector *connector, @@ -6721,24 +6723,61 @@ static void update_displayid_info(struct drm_connector *connector, struct drm_display_info *info = &connector->display_info; const struct displayid_block *block; struct displayid_iter iter; + const u8 *section = NULL; displayid_iter_edid_begin(drm_edid, &iter); displayid_iter_for_each(block, &iter) { + if (section != iter.section) { + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n", + connector->base.id, connector->name, + displayid_version(&iter), + displayid_primary_use(&iter)); + if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 && + (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR || + displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR)) + info->non_desktop = true; + section = iter.section; + } + drm_dbg_kms(connector->dev, - "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n", + "[CONNECTOR:%d:%s] DisplayID block tag 0x%02x, rev 0x%02x, size %u\n", connector->base.id, connector->name, - displayid_version(&iter), - displayid_primary_use(&iter)); + block->tag, block->rev, block->num_bytes); + if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 && - (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR || - displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR)) - info->non_desktop = true; + block->tag == DATA_BLOCK_2_DISPLAY_PARAMETERS) { + const struct displayid_display_params_block *params = + (const struct displayid_display_params_block *)block; + u8 tech; + + if (block->num_bytes < DISPLAYID_DISPLAY_PARAMS_MIN_LEN) { + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] DisplayID Display Parameters block too short (%u < %zu)\n", + connector->base.id, connector->name, + block->num_bytes, + DISPLAYID_DISPLAY_PARAMS_MIN_LEN); + continue; + } - /* - * We're only interested in the base section here, no need to - * iterate further. - */ - break; + tech = FIELD_GET(DISPLAYID_DISPLAY_PARAMS_DEVICE_TECH, + params->device_tech_byte); + + drm_dbg_kms(connector->dev, + "[CONNECTOR:%d:%s] DisplayID Display Parameters: device technology %u\n", + connector->base.id, connector->name, tech); + + switch (tech) { + case 1: /* LCD */ + info->did_panel_type = DRM_MODE_PANEL_TYPE_LCD; + break; + case 2: /* OLED */ + info->did_panel_type = DRM_MODE_PANEL_TYPE_OLED; + break; + default: + break; + } + } } displayid_iter_end(&iter); } diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index c398dbc68bbc..b95aec34ddb7 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -899,6 +899,12 @@ struct drm_display_info { * @amd_vsdb: AMD-specific VSDB information. */ struct drm_amd_vsdb_info amd_vsdb; + + /** + * @did_panel_type: Panel type from DisplayID Display Parameters + * Data Block (tag 0x21). Uses DRM_MODE_PANEL_TYPE_* constants. + */ + u8 did_panel_type; }; int drm_display_info_set_bus_formats(struct drm_display_info *info, diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h index 3693d82b5279..d7ca1040b92e 100644 --- a/include/uapi/drm/drm_mode.h +++ b/include/uapi/drm/drm_mode.h @@ -169,6 +169,7 @@ extern "C" { /* Panel type property */ #define DRM_MODE_PANEL_TYPE_UNKNOWN 0 #define DRM_MODE_PANEL_TYPE_OLED 1 +#define DRM_MODE_PANEL_TYPE_LCD 2 /* * DRM_MODE_ROTATE_<degrees> -- 2.43.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block 2026-05-14 6:54 ` [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block Chenyu Chen @ 2026-05-15 8:23 ` Jani Nikula 0 siblings, 0 replies; 4+ messages in thread From: Jani Nikula @ 2026-05-15 8:23 UTC (permalink / raw) To: Chenyu Chen, amd-gfx, dri-devel Cc: Harry Wentland, Leo Li, Ray Wu, Limonciello Mario, Chenyu Chen, Mario Limonciello On Thu, 14 May 2026, Chenyu Chen <chen-yu.chen@amd.com> wrote: > Parse the Display Parameters Data Block (tag 0x21) defined in > DisplayID v2.1a Section 4.2.6. Extract the Display Device Technology > field from payload byte 27, bits [6:4], which indicates whether the > panel is LCD (001b) or OLED (010b). > > Store the result in drm_display_info.did_panel_type so that downstream > drivers can use it for panel-type-dependent behavior. > > Assisted-by: Copilot:Claude-Opus-4.6 > Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com> > Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> > --- > drivers/gpu/drm/drm_displayid_internal.h | 25 ++++++++++ > drivers/gpu/drm/drm_edid.c | 61 +++++++++++++++++++----- > include/drm/drm_connector.h | 6 +++ > include/uapi/drm/drm_mode.h | 1 + > 4 files changed, 82 insertions(+), 11 deletions(-) > > diff --git a/drivers/gpu/drm/drm_displayid_internal.h b/drivers/gpu/drm/drm_displayid_internal.h > index 5b1b32f73516..e0f7c54d2987 100644 > --- a/drivers/gpu/drm/drm_displayid_internal.h > +++ b/drivers/gpu/drm/drm_displayid_internal.h > @@ -142,6 +142,31 @@ struct displayid_formula_timing_block { > struct displayid_formula_timings_9 timings[]; > } __packed; > > +/* > + * DisplayID v2.x Display Parameters Data Block (tag 0x21). > + * > + * Per VESA DisplayID v2.1a, Section 4.2.6, Table 4-14: > + * Offset 0x1E (payload byte 27) contains Native Color Depth and > + * Display Device Technology fields. > + * bits [2:0] = Native Color Depth > + * bit [3] = RESERVED > + * bits [6:4] = Display Device Technology > + * 000b = not specified, 001b = LCD, 010b = OLED, others reserved > + * bit [7] = Display Device Theme Preference > + */ > +#define DISPLAYID_DISPLAY_PARAMS_DEVICE_TECH GENMASK(6, 4) > + > +struct displayid_display_params_block { > + struct displayid_block base; > + u8 payload[27]; > + u8 device_tech_byte; /* bits [6:4] = Display Device Technology */ > + u8 reserved; > +} __packed; > + > +#define DISPLAYID_DISPLAY_PARAMS_MIN_LEN \ > + (sizeof(struct displayid_display_params_block) - \ > + sizeof(struct displayid_block)) > + > #define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0) > #define DISPLAYID_VESA_MSO_MODE GENMASK(6, 5) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 8031f021d4d0..9b160a878df4 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -6713,6 +6713,8 @@ static void drm_reset_display_info(struct drm_connector *connector) > > info->source_physical_address = CEC_PHYS_ADDR_INVALID; > memset(&info->amd_vsdb, 0, sizeof(info->amd_vsdb)); > + > + info->did_panel_type = DRM_MODE_PANEL_TYPE_UNKNOWN; > } > > static void update_displayid_info(struct drm_connector *connector, > @@ -6721,24 +6723,61 @@ static void update_displayid_info(struct drm_connector *connector, > struct drm_display_info *info = &connector->display_info; > const struct displayid_block *block; > struct displayid_iter iter; > + const u8 *section = NULL; > > displayid_iter_edid_begin(drm_edid, &iter); > displayid_iter_for_each(block, &iter) { > + if (section != iter.section) { > + drm_dbg_kms(connector->dev, > + "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n", > + connector->base.id, connector->name, > + displayid_version(&iter), > + displayid_primary_use(&iter)); > + if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 && > + (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR || > + displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR)) > + info->non_desktop = true; > + section = iter.section; > + } What is this even supposed to do? > + > drm_dbg_kms(connector->dev, > - "[CONNECTOR:%d:%s] DisplayID extension version 0x%02x, primary use 0x%02x\n", > + "[CONNECTOR:%d:%s] DisplayID block tag 0x%02x, rev 0x%02x, size %u\n", > connector->base.id, connector->name, > - displayid_version(&iter), > - displayid_primary_use(&iter)); > + block->tag, block->rev, block->num_bytes); > + > if (displayid_version(&iter) == DISPLAY_ID_STRUCTURE_VER_20 && > - (displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_VR || > - displayid_primary_use(&iter) == PRIMARY_USE_HEAD_MOUNTED_AR)) > - info->non_desktop = true; > + block->tag == DATA_BLOCK_2_DISPLAY_PARAMETERS) { > + const struct displayid_display_params_block *params = > + (const struct displayid_display_params_block *)block; > + u8 tech; > + > + if (block->num_bytes < DISPLAYID_DISPLAY_PARAMS_MIN_LEN) { > + drm_dbg_kms(connector->dev, > + "[CONNECTOR:%d:%s] DisplayID Display Parameters block too short (%u < %zu)\n", > + connector->base.id, connector->name, > + block->num_bytes, > + DISPLAYID_DISPLAY_PARAMS_MIN_LEN); > + continue; > + } > > - /* > - * We're only interested in the base section here, no need to > - * iterate further. > - */ > - break; > + tech = FIELD_GET(DISPLAYID_DISPLAY_PARAMS_DEVICE_TECH, > + params->device_tech_byte); > + > + drm_dbg_kms(connector->dev, > + "[CONNECTOR:%d:%s] DisplayID Display Parameters: device technology %u\n", > + connector->base.id, connector->name, tech); > + > + switch (tech) { > + case 1: /* LCD */ > + info->did_panel_type = DRM_MODE_PANEL_TYPE_LCD; > + break; > + case 2: /* OLED */ > + info->did_panel_type = DRM_MODE_PANEL_TYPE_OLED; > + break; > + default: > + break; > + } > + } Please tell copilot to not add so much crap in the iterator block. Add functions. Add the first function as a refactor for non_desktop, add more stuff on top, i.e. split this into multiple patches. BR, Jani. > } > displayid_iter_end(&iter); > } > diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h > index c398dbc68bbc..b95aec34ddb7 100644 > --- a/include/drm/drm_connector.h > +++ b/include/drm/drm_connector.h > @@ -899,6 +899,12 @@ struct drm_display_info { > * @amd_vsdb: AMD-specific VSDB information. > */ > struct drm_amd_vsdb_info amd_vsdb; > + > + /** > + * @did_panel_type: Panel type from DisplayID Display Parameters > + * Data Block (tag 0x21). Uses DRM_MODE_PANEL_TYPE_* constants. > + */ > + u8 did_panel_type; > }; > > int drm_display_info_set_bus_formats(struct drm_display_info *info, > diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h > index 3693d82b5279..d7ca1040b92e 100644 > --- a/include/uapi/drm/drm_mode.h > +++ b/include/uapi/drm/drm_mode.h > @@ -169,6 +169,7 @@ extern "C" { > /* Panel type property */ > #define DRM_MODE_PANEL_TYPE_UNKNOWN 0 > #define DRM_MODE_PANEL_TYPE_OLED 1 > +#define DRM_MODE_PANEL_TYPE_LCD 2 > > /* > * DRM_MODE_ROTATE_<degrees> -- Jani Nikula, Intel ^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 2/2] drm/amd/display: use DisplayID panel type in dm_set_panel_type 2026-05-14 6:54 [PATCH 0/2] drm: detect panel type from DisplayID 2.x Chenyu Chen 2026-05-14 6:54 ` [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block Chenyu Chen @ 2026-05-14 6:54 ` Chenyu Chen 1 sibling, 0 replies; 4+ messages in thread From: Chenyu Chen @ 2026-05-14 6:54 UTC (permalink / raw) To: amd-gfx, dri-devel Cc: Harry Wentland, Leo Li, Ray Wu, Limonciello Mario, Jani Nikula, Chenyu Chen, Mario Limonciello Wire up the newly parsed did_panel_type from drm_display_info into amdgpu_dm's panel type detection path. When neither the AMD VSDB nor DPCD determines the panel type, fall back to the DisplayID Display Device Technology field to set PANEL_TYPE_LCD or PANEL_TYPE_OLED accordingly. Assisted-by: Copilot:Claude-Opus-4.6 Signed-off-by: Chenyu Chen <chen-yu.chen@amd.com> Reviewed-by: Mario Limonciello <mario.limonciello@amd.com> --- drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) 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 e42a5eecdf46..353a4982333d 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -3944,11 +3944,13 @@ static void dm_set_panel_type(struct amdgpu_dm_connector *aconnector) link->panel_type = PANEL_TYPE_OLED; } - /* - * TODO: get panel type from DID2 that has device technology field - * to specify if it's OLED or not. But we need to wait for DID2 - * support in DC and EDID parser to be able to use it here. - */ + /* If VSDB and DPCD didn't determine panel type, check DID */ + if (link->panel_type == PANEL_TYPE_NONE) { + if (display_info->did_panel_type == DRM_MODE_PANEL_TYPE_LCD) + link->panel_type = PANEL_TYPE_LCD; + else if (display_info->did_panel_type == DRM_MODE_PANEL_TYPE_OLED) + link->panel_type = PANEL_TYPE_OLED; + } if (link->panel_type == PANEL_TYPE_NONE) { struct drm_amd_vsdb_info *vsdb = &display_info->amd_vsdb; -- 2.43.0 ^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-05-15 8:24 UTC | newest] Thread overview: 4+ messages (download: mbox.gz follow: Atom feed -- links below jump to the message on this page -- 2026-05-14 6:54 [PATCH 0/2] drm: detect panel type from DisplayID 2.x Chenyu Chen 2026-05-14 6:54 ` [PATCH 1/2] drm/edid: parse panel type from DisplayID 2.x Display Parameters block Chenyu Chen 2026-05-15 8:23 ` Jani Nikula 2026-05-14 6:54 ` [PATCH 2/2] drm/amd/display: use DisplayID panel type in dm_set_panel_type Chenyu Chen
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