On Sun, 26 Feb 2023, Yaroslav Bolyukin <iam@xxxxxxx> wrote:
> As per DisplayID v2.0 Errata E9 spec "DSC pass-through timing support"
> VESA vendor-specific data block may contain target DSC bits per pixel
> fields
>
> Signed-off-by: Yaroslav Bolyukin <iam@xxxxxxx>
> ---
> drivers/gpu/drm/drm_edid.c | 38 +++++++++++++++++++++++++------------
> include/drm/drm_connector.h | 6 ++++++
> include/drm/drm_displayid.h | 4 ++++
> 3 files changed, 36 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 3d0a4da661bc..aa88ac82cbe0 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -6338,7 +6338,7 @@ static void drm_parse_vesa_mso_data(struct drm_connector *connector,
> if (oui(vesa->oui[0], vesa->oui[1], vesa->oui[2]) != VESA_IEEE_OUI)
> return;
>
> - if (sizeof(*vesa) != sizeof(*block) + block->num_bytes) {
> + if (block->num_bytes < 5) {
> drm_dbg_kms(connector->dev,
> "[CONNECTOR:%d:%s] Unexpected VESA vendor block size\n",
> connector->base.id, connector->name);
> @@ -6361,24 +6361,37 @@ static void drm_parse_vesa_mso_data(struct drm_connector *connector,
> break;
> }
>
> - if (!info->mso_stream_count) {
> - info->mso_pixel_overlap = 0;
> - return;
> - }
> + info->mso_pixel_overlap = 0;
> +
> + if (info->mso_stream_count) {
> + info->mso_pixel_overlap = FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->mso);
> +
> + if (info->mso_pixel_overlap > 8) {
> + drm_dbg_kms(connector->dev,
> + "[CONNECTOR:%d:%s] Reserved MSO pixel overlap value %u\n",
> + connector->base.id, connector->name,
> + info->mso_pixel_overlap);
> + info->mso_pixel_overlap = 8;
> + }
>
> - info->mso_pixel_overlap = FIELD_GET(DISPLAYID_VESA_MSO_OVERLAP, vesa->mso);
> - if (info->mso_pixel_overlap > 8) {
> drm_dbg_kms(connector->dev,
> - "[CONNECTOR:%d:%s] Reserved MSO pixel overlap value %u\n",
> + "[CONNECTOR:%d:%s] MSO stream count %u, pixel overlap %u\n",
> connector->base.id, connector->name,
> - info->mso_pixel_overlap);
> - info->mso_pixel_overlap = 8;
> + info->mso_stream_count, info->mso_pixel_overlap);
> + }
> +
> + if (block->num_bytes < 7) {
> + /* DSC bpp is optional */
> + return;
> }
>
> + info->dp_dsc_bpp = FIELD_GET(DISPLAYID_VESA_DSC_BPP_INT, vesa->dsc_bpp_int) * 16
> + + FIELD_GET(DISPLAYID_VESA_DSC_BPP_FRACT, vesa->dsc_bpp_fract);
> +
Matter of taste, but I'd probably use << 4 and |. *shrug*
> drm_dbg_kms(connector->dev,
> - "[CONNECTOR:%d:%s] MSO stream count %u, pixel overlap %u\n",
> + "[CONNECTOR:%d:%s] DSC bits per pixel %u\n",
> connector->base.id, connector->name,
> - info->mso_stream_count, info->mso_pixel_overlap);
> + info->dp_dsc_bpp);
> }
>
> static void drm_update_mso(struct drm_connector *connector,
> @@ -6425,6 +6438,7 @@ static void drm_reset_display_info(struct drm_connector *connector)
> info->mso_stream_count = 0;
> info->mso_pixel_overlap = 0;
> info->max_dsc_bpp = 0;
> + info->dp_dsc_bpp = 0;
>
> kfree(info->vics);
> info->vics = NULL;
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 7b5048516185..1d01e0146a7f 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -719,6 +719,12 @@ struct drm_display_info {
> */
> u32 max_dsc_bpp;
>
> + /**
> + * @dp_dsc_bpp: DP Display-Stream-Compression (DSC) timing's target
> + * DST bits per pixel in 6.4 fixed point format. 0 means undefined
DST?
Reviewed-by: Jani Nikula <jani.nikula@xxxxxxxxx>
> + */
> + u16 dp_dsc_bpp;
> +
> /**
> * @vics: Array of vics_len VICs. Internal to EDID parsing.
> */
> diff --git a/include/drm/drm_displayid.h b/include/drm/drm_displayid.h
> index 49649eb8447e..0fc3afbd1675 100644
> --- a/include/drm/drm_displayid.h
> +++ b/include/drm/drm_displayid.h
> @@ -131,12 +131,16 @@ struct displayid_detailed_timing_block {
>
> #define DISPLAYID_VESA_MSO_OVERLAP GENMASK(3, 0)
> #define DISPLAYID_VESA_MSO_MODE GENMASK(6, 5)
> +#define DISPLAYID_VESA_DSC_BPP_INT GENMASK(5, 0)
> +#define DISPLAYID_VESA_DSC_BPP_FRACT GENMASK(3, 0)
>
> struct displayid_vesa_vendor_specific_block {
> struct displayid_block base;
> u8 oui[3];
> u8 data_structure_type;
> u8 mso;
> + u8 dsc_bpp_int;
> + u8 dsc_bpp_fract;
> } __packed;
>
> /* DisplayID iteration */
--
Jani Nikula, Intel Open Source Graphics Center
