From 18a9cbbe55801694b34328f6313d38c8f657966b Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Tue, 31 Aug 2021 17:17:33 +0300 Subject: 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 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 72 insertions(+) (limited to 'drivers/gpu/drm/drm_edid.c') 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; } -- cgit v1.2.3