From 18a9cbbe55801694b34328f6313d38c8f657966b Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Tue, 31 Aug 2021 17:17:33 +0300 Subject: [PATCH] drm/edid: parse the DisplayID v2.0 VESA vendor block for MSO The VESA Organization Vendor-Specific Data Block, defined in VESA DisplayID Standard v2.0, specifies the eDP Multi-SST Operation (MSO) stream count and segment pixel overlap. DisplayID v1.3 has Appendix B: DisplayID as an EDID Extension, describing how DisplayID sections may be embedded in EDID extension blocks. DisplayID v2.0 does not have such a section, perhaps implying that DisplayID v2.0 data should not be included in EDID extensions, but rather in a "pure" DisplayID structure at its own DDC address pair A4h/A5h, as described in VESA E-DDC Standard v1.3 chapter 3. However, in practice, displays out in the field have embedded DisplayID v2.0 data blocks in EDID extensions, including, in particular, some eDP MSO displays, where a pure DisplayID structure is not available at all. Parse the MSO data from the DisplayID data block. Do it as part of drm_add_display_info(), extending it to parse also DisplayID data to avoid requiring extra calls to update the information. v2: Check for VESA OUI (Ville) Reviewed-by: Uma Shankar Acked-by: Maxime Ripard Signed-off-by: Jani Nikula Link: https://patchwork.freedesktop.org/patch/msgid/73ca2887e7b37880690f5c9ba4594c9cd1170669.1630419362.git.jani.nikula@intel.com --- drivers/gpu/drm/drm_edid.c | 72 +++++++++++++++++++++++++++++++++++++ include/drm/drm_connector.h | 12 +++++++ include/drm/drm_displayid.h | 13 +++++++ 3 files changed, 97 insertions(+) diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 92974b1478bc..c45c225267ca 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -28,6 +28,7 @@ * DEALINGS IN THE SOFTWARE. */ +#include #include #include #include @@ -5145,6 +5146,71 @@ void drm_get_monitor_range(struct drm_connector *connector, info->monitor_range.max_vfreq); } +static void drm_parse_vesa_mso_data(struct drm_connector *connector, + const struct displayid_block *block) +{ + struct displayid_vesa_vendor_specific_block *vesa = + (struct displayid_vesa_vendor_specific_block *)block; + struct drm_display_info *info = &connector->display_info; + + if (block->num_bytes < 3) { + drm_dbg_kms(connector->dev, "Unexpected vendor block size %u\n", + block->num_bytes); + return; + } + + if (oui(vesa->oui[0], vesa->oui[1], vesa->oui[2]) != VESA_IEEE_OUI) + return; + + if (sizeof(*vesa) != sizeof(*block) + block->num_bytes) { + drm_dbg_kms(connector->dev, "Unexpected VESA vendor block size\n"); + return; + } + + switch (FIELD_GET(DISPLAYID_VESA_MSO_MODE, vesa->mso)) { + default: + drm_dbg_kms(connector->dev, "Reserved MSO mode value\n"); + fallthrough; + case 0: + info->mso_stream_count = 0; + break; + case 1: + info->mso_stream_count = 2; /* 2 or 4 links */ + break; + case 2: + info->mso_stream_count = 4; /* 4 links */ + break; + } + + if (!info->mso_stream_count) { + info->mso_pixel_overlap = 0; + return; + } + + info->mso_pixel_overlap = FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->mso); + if (info->mso_pixel_overlap > 8) { + drm_dbg_kms(connector->dev, "Reserved MSO pixel overlap value %u\n", + info->mso_pixel_overlap); + info->mso_pixel_overlap = 8; + } + + drm_dbg_kms(connector->dev, "MSO stream count %u, pixel overlap %u\n", + info->mso_stream_count, info->mso_pixel_overlap); +} + +static void drm_update_mso(struct drm_connector *connector, const struct edid *edid) +{ + const struct displayid_block *block; + struct displayid_iter iter; + + displayid_iter_edid_begin(edid, &iter); + displayid_iter_for_each(block, &iter) { + if (block->tag == DATA_BLOCK_2_VENDOR_SPECIFIC) + drm_parse_vesa_mso_data(connector, block); + } + displayid_iter_end(&iter); +} + /* A connector has no EDID information, so we've got no EDID to compute quirks from. Reset * all of the values which would have been set from EDID */ @@ -5168,6 +5234,9 @@ drm_reset_display_info(struct drm_connector *connector) info->non_desktop = 0; memset(&info->monitor_range, 0, sizeof(info->monitor_range)); + + info->mso_stream_count = 0; + info->mso_pixel_overlap = 0; } u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edid) @@ -5246,6 +5315,9 @@ u32 drm_add_display_info(struct drm_connector *connector, const struct edid *edi info->color_formats |= DRM_COLOR_FORMAT_YCRCB444; if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB422) info->color_formats |= DRM_COLOR_FORMAT_YCRCB422; + + drm_update_mso(connector, edid); + return quirks; } diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 79fa34e5ccdb..379746d3266f 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -590,6 +590,18 @@ struct drm_display_info { * @monitor_range: Frequency range supported by monitor range descriptor */ struct drm_monitor_range_info monitor_range; + + /** + * @mso_stream_count: eDP Multi-SST Operation (MSO) stream count from + * the DisplayID VESA vendor block. 0 for conventional Single-Stream + * Transport (SST), or 2 or 4 MSO streams. + */ + u8 mso_stream_count; + + /** + * @mso_pixel_overlap: eDP MSO segment pixel overlap, 0-8 pixels. + */ + u8 mso_pixel_overlap; }; int drm_display_info_set_bus_formats(struct drm_display_info *info, diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h index 79771091771a..7ffbd9f7bfc7 100644 --- a/include/drm/drm_displayid.h +++ b/include/drm/drm_displayid.h @@ -23,9 +23,12 @@ #define DRM_DISPLAYID_H #include +#include struct edid; +#define VESA_IEEE_OUI 0x3a0292 + /* DisplayID Structure versions */ #define DISPLAY_ID_STRUCTURE_VER_12 0x12 #define DISPLAY_ID_STRUCTURE_VER_20 0x20 @@ -126,6 +129,16 @@ struct displayid_detailed_timing_block { struct displayid_detailed_timings_1 timings[]; }; +#define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0) +#define DISPLAYID_VESA_MSO_MODE GENMASK(6, 5) + +struct displayid_vesa_vendor_specific_block { + struct displayid_block base; + u8 oui[3]; + u8 data_structure_type; + u8 mso; +} __packed; + /* DisplayID iteration */ struct displayid_iter { const struct edid *edid; -- 2.39.5