On Sun, 13 Mar 2022, Lee Shawn C <shawn.c....@intel.com> wrote: > According to HDMI 2.1 spec. > > "The HDMI Forum EDID Extension Override Data Block (HF-EEODB) > is utilized by Sink Devices to provide an alternate method to > indicate an EDID Extension Block count larger than 1, while > avoiding the need to present a VESA Block Map in the first > E-EDID Extension Block." > > It is a mandatory for HDMI 2.1 protocol compliance as well. > This patch help to know how many HF_EEODB blocks report by sink > and read allo HF_EEODB blocks back. > > v2: support to find CEA block, check EEODB block format, and return > available block number in drm_edid_read_hf_eeodb_blk_count(). > > Cc: Jani Nikula <jani.nik...@linux.intel.com> > Cc: Ville Syrjala <ville.syrj...@linux.intel.com> > Cc: Ankit Nautiyal <ankit.k.nauti...@intel.com> > Cc: Drew Davenport <ddavenp...@chromium.org> > Cc: intel-gfx <intel-gfx@lists.freedesktop.org> > Signed-off-by: Lee Shawn C <shawn.c....@intel.com> > --- > drivers/gpu/drm/drm_connector.c | 8 +++- > drivers/gpu/drm/drm_edid.c | 71 +++++++++++++++++++++++++++++++-- > include/drm/drm_edid.h | 1 + > 3 files changed, 74 insertions(+), 6 deletions(-) > > diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c > index a50c82bc2b2f..16011023c12e 100644 > --- a/drivers/gpu/drm/drm_connector.c > +++ b/drivers/gpu/drm/drm_connector.c > @@ -2129,7 +2129,7 @@ int drm_connector_update_edid_property(struct > drm_connector *connector, > const struct edid *edid) > { > struct drm_device *dev = connector->dev; > - size_t size = 0; > + size_t size = 0, hf_eeodb_blk_count; > int ret; > const struct edid *old_edid; > > @@ -2137,8 +2137,12 @@ int drm_connector_update_edid_property(struct > drm_connector *connector, > if (connector->override_edid) > return 0; > > - if (edid) > + if (edid) { > size = EDID_LENGTH * (1 + edid->extensions); > + hf_eeodb_blk_count = drm_edid_read_hf_eeodb_blk_count(edid); > + if (hf_eeodb_blk_count) > + size = EDID_LENGTH * (1 + hf_eeodb_blk_count);
This approach does not scale. If the number of extensions and thus the total EDID size depend on HF-EEODB, this *must* be abstracted. Consider, for example, drm_edid_duplicate(), which only looks at edid->extensions. A subsequent HF-EEODB aware access on an EDID duplicated using drm_edid_duplicate() will access beyond the allocated buffer. Yes, it's a lot of work to introduce drm_edid_size() and drm_edid_extension_count() or similar, and use them everywhere, but this is what we must do. It's a lot more work to try to take HF-EEODB into account everywhere. The latter is going to be riddled with bugs with everyone doing it a little different. > + } > > /* Set the display info, using edid if available, otherwise > * resetting the values to defaults. This duplicates the work > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 9fa84881fbba..5ae4e83fa5e3 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -1992,6 +1992,7 @@ struct edid *drm_do_get_edid(struct drm_connector > *connector, > { > int i, j = 0, valid_extensions = 0; > u8 *edid, *new; > + size_t hf_eeodb_blk_count; > struct edid *override; > > override = drm_get_override_edid(connector); > @@ -2051,7 +2052,35 @@ struct edid *drm_do_get_edid(struct drm_connector > *connector, > } > > kfree(edid); > + return (struct edid *)new; > + } > + > + hf_eeodb_blk_count = drm_edid_read_hf_eeodb_blk_count((struct edid > *)edid); > + if (hf_eeodb_blk_count >= 2) { > + new = krealloc(edid, (hf_eeodb_blk_count + 1) * EDID_LENGTH, > GFP_KERNEL); > + if (!new) > + goto out; > edid = new; > + > + valid_extensions = hf_eeodb_blk_count - 1; > + for (j = 2; j <= hf_eeodb_blk_count; j++) { > + u8 *block = edid + j * EDID_LENGTH; > + > + for (i = 0; i < 4; i++) { > + if (get_edid_block(data, block, j, EDID_LENGTH)) > + goto out; > + if (drm_edid_block_valid(block, j, false, NULL)) > + break; > + } > + > + if (i == 4) > + valid_extensions--; > + } > + > + if (valid_extensions != hf_eeodb_blk_count - 1) { > + DRM_ERROR("Not able to retrieve proper EDID contain > HF-EEODB data.\n"); > + goto out; > + } > } > > return (struct edid *)edid; > @@ -3315,15 +3344,17 @@ add_detailed_modes(struct drm_connector *connector, > struct edid *edid, > #define VIDEO_BLOCK 0x02 > #define VENDOR_BLOCK 0x03 > #define SPEAKER_BLOCK 0x04 > -#define HDR_STATIC_METADATA_BLOCK 0x6 > -#define USE_EXTENDED_TAG 0x07 > -#define EXT_VIDEO_CAPABILITY_BLOCK 0x00 > +#define EXT_VIDEO_CAPABILITY_BLOCK 0x00 > +#define HDR_STATIC_METADATA_BLOCK 0x06 > +#define USE_EXTENDED_TAG 0x07 > #define EXT_VIDEO_DATA_BLOCK_420 0x0E > -#define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F > +#define EXT_VIDEO_CAP_BLOCK_Y420CMDB 0x0F > +#define EXT_VIDEO_HF_EEODB_DATA_BLOCK 0x78 > #define EDID_BASIC_AUDIO (1 << 6) > #define EDID_CEA_YCRCB444 (1 << 5) > #define EDID_CEA_YCRCB422 (1 << 4) > #define EDID_CEA_VCDB_QS (1 << 6) > +#define HF_EEODB_LENGTH 2 > > /* > * Search EDID for CEA extension block. > @@ -4274,9 +4305,41 @@ static bool cea_db_is_y420vdb(const u8 *db) > return true; > } > > +static bool cea_db_is_hdmi_forum_eeodb(const u8 *db) > +{ > + if (cea_db_tag(db) != USE_EXTENDED_TAG) > + return false; > + > + if (cea_db_payload_len(db) != HF_EEODB_LENGTH) > + return false; > + > + if (cea_db_extended_tag(db) != EXT_VIDEO_HF_EEODB_DATA_BLOCK) > + return false; > + > + return true; > +} > + > #define for_each_cea_db(cea, i, start, end) \ > for ((i) = (start); (i) < (end) && (i) + > cea_db_payload_len(&(cea)[(i)]) < (end); (i) += > cea_db_payload_len(&(cea)[(i)]) + 1) > > +size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid) > +{ > + const u8 *cea; > + int i, start, end, cea_ext_index = 0, displayid_ext_index = 0; > + > + if (edid->extensions) { > + cea = drm_find_cea_extension(edid, &cea_ext_index, > &displayid_ext_index); > + > + if (cea && !cea_db_offsets(cea, &start, &end)) > + for_each_cea_db(cea, i, start, end) > + if (cea_db_is_hdmi_forum_eeodb(&cea[i])) > + return cea[i + 2]; > + } > + > + return 0; > +} > +EXPORT_SYMBOL_GPL(drm_edid_read_hf_eeodb_blk_count); This should be static and not exported. BR, Jani. > + > static void drm_parse_y420cmdb_bitmap(struct drm_connector *connector, > const u8 *db) > { > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h > index 144c495b99c4..585f0ed932d4 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -593,5 +593,6 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, > const u8 *drm_find_edid_extension(const struct edid *edid, > int ext_id, int *ext_index); > > +size_t drm_edid_read_hf_eeodb_blk_count(const struct edid *edid); > > #endif /* __DRM_EDID_H__ */ -- Jani Nikula, Intel Open Source Graphics Center