On Mon, Aug 30, 2021 at 01:29:01PM +0300, Jani Nikula wrote:
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.
Signed-off-by: Jani Nikula jani.nikula@intel.com
drivers/gpu/drm/drm_edid.c | 63 +++++++++++++++++++++++++++++++++++++ include/drm/drm_connector.h | 12 +++++++ include/drm/drm_displayid.h | 11 +++++++ 3 files changed, 86 insertions(+)
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 6325877c5fd6..7e8083068f3f 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -28,6 +28,7 @@
- DEALINGS IN THE SOFTWARE.
*/
+#include <linux/bitfield.h> #include <linux/hdmi.h> #include <linux/i2c.h> #include <linux/kernel.h> @@ -5148,6 +5149,62 @@ 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 (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)
Don't we need to check the OUI to make sure the block is the right type? I don't have the v2 spec at hand atm, but I presume a vendor specific block could contain all kinds of different things?
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
*/ @@ -5171,6 +5228,9 @@ 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) @@ -5249,6 +5309,9 @@ 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..b18611e016a2 100644 --- a/include/drm/drm_displayid.h +++ b/include/drm/drm_displayid.h @@ -23,6 +23,7 @@ #define DRM_DISPLAYID_H
#include <linux/types.h> +#include <linux/bits.h>
struct edid;
@@ -126,6 +127,16 @@ 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; -- 2.20.1