| Message ID | 20220317124202.14189-4-shawn.c.lee@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | enhanced edid driver compatibility | expand |
On Thu, 17 Mar 2022, Lee Shawn C <shawn.c.lee@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. It still just boggles my mind that they've implemented something like this. They cite avoiding the EDID Block Map as the rationale... but it's been optional since E-EDID structure v1.4, published in 2006. 15+ years ago. Can anyone tell me a sane reason for this? What does it provide that E-EDID 1.4 does not? Do they want to use E-EDID v1.3 with this? Why? BR, Jani. > > 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.nikula@linux.intel.com> > Cc: Ville Syrjala <ville.syrjala@linux.intel.com> > Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com> > Cc: intel-gfx <intel-gfx@lists.freedesktop.org> > Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com> > --- > drivers/gpu/drm/drm_connector.c | 8 +++- > drivers/gpu/drm/drm_edid.c | 71 +++++++++++++++++++++++++++++++-- > include/drm/drm_edid.h | 2 +- > 3 files changed, 74 insertions(+), 7 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); > + } > > /* 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 ef65dd97d700..890038758660 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. > @@ -4273,9 +4304,41 @@ 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, ext_index = 0; > + > + if (edid->extensions) { > + cea = drm_find_cea_extension(edid, &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); > + > 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..5549da7bd7be 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -592,6 +592,6 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, > u8 video_code); > 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__ */
On Wed, 23 Mar 2022, Jani Nikula <jani.nikula@intel.com> wrote: > On Thu, 17 Mar 2022, Lee Shawn C <shawn.c.lee@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. > > It still just boggles my mind that they've implemented something like > this. They cite avoiding the EDID Block Map as the rationale... but it's > been optional since E-EDID structure v1.4, published in 2006. 15+ years > ago. > > Can anyone tell me a sane reason for this? What does it provide that > E-EDID 1.4 does not? Do they want to use E-EDID v1.3 with this? Why? Oh, and the main problem with the whole thing, and this implementation? If you have a struct edid *, there's no way way to tell if whoever allocated the memory or copied the block was actually HF-EEODB aware. Basically we'd have to audit every single piece of EDID handling code across all drivers to see if they handle HF-EEODB properly. If we don't, it's a question of time a struct edid * with HF-EEODB but no memory allocated for the extensions gets passed to a function that understands it, and overflows the buffer. Simon and Daniel also tell me on IRC we can't just modify the base block extension count to match HF-EEODB to dodge the problem, because the EDID gets exposed to userspace. BR, Jani. > > BR, > Jani. > > >> >> 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.nikula@linux.intel.com> >> Cc: Ville Syrjala <ville.syrjala@linux.intel.com> >> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com> >> Cc: intel-gfx <intel-gfx@lists.freedesktop.org> >> Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com> >> --- >> drivers/gpu/drm/drm_connector.c | 8 +++- >> drivers/gpu/drm/drm_edid.c | 71 +++++++++++++++++++++++++++++++-- >> include/drm/drm_edid.h | 2 +- >> 3 files changed, 74 insertions(+), 7 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); >> + } >> >> /* 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 ef65dd97d700..890038758660 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. >> @@ -4273,9 +4304,41 @@ 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, ext_index = 0; >> + >> + if (edid->extensions) { >> + cea = drm_find_cea_extension(edid, &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); >> + >> 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..5549da7bd7be 100644 >> --- a/include/drm/drm_edid.h >> +++ b/include/drm/drm_edid.h >> @@ -592,6 +592,6 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, >> u8 video_code); >> 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__ */
On Wednesday, March 23rd, 2022 at 13:02, Jani Nikula <jani.nikula@intel.com> wrote: > Simon and Daniel also tell me on IRC we can't just modify the base block > extension count to match HF-EEODB to dodge the problem, because the EDID > gets exposed to userspace. I'm not familiar how the EDID blob gets exposed to user-space. If the EDID data gets copied when creating the blob, and the blob is created before the kernel mutates the EDID to accomodate for HF-EEODB, then this proposal might still be workable.
On Wed, 23 Mar 2022, Simon Ser <contact@emersion.fr> wrote: > On Wednesday, March 23rd, 2022 at 13:02, Jani Nikula <jani.nikula@intel.com> wrote: > >> Simon and Daniel also tell me on IRC we can't just modify the base block >> extension count to match HF-EEODB to dodge the problem, because the EDID >> gets exposed to userspace. > > I'm not familiar how the EDID blob gets exposed to user-space. If the > EDID data gets copied when creating the blob, and the blob is created > before the kernel mutates the EDID to accomodate for HF-EEODB, then > this proposal might still be workable. You'd still end up with tracking separate copies of the EDID, which is not necessarily easier. There are almost 70 calls to update the connector EDID property that gets exposed to userspace, and the call sites would need to know which copy to pass. BR, Jani.
On Wed, Mar 23, 2022 at 12:11:50PM +0200, Jani Nikula wrote: > On Thu, 17 Mar 2022, Lee Shawn C <shawn.c.lee@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. > > It still just boggles my mind that they've implemented something like > this. They cite avoiding the EDID Block Map as the rationale... but it's > been optional since E-EDID structure v1.4, published in 2006. 15+ years > ago. > > Can anyone tell me a sane reason for this? What does it provide that > E-EDID 1.4 does not? Do they want to use E-EDID v1.3 with this? Why? Looks to be pretty much the same approach as the DPCD extended receiver cap mess we already have to deal with. So I presume this is a hack to avoid breaking some garbage source devices that explode when they see too many extension blocks, or something along those lines.
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); + } /* 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 ef65dd97d700..890038758660 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. @@ -4273,9 +4304,41 @@ 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, ext_index = 0; + + if (edid->extensions) { + cea = drm_find_cea_extension(edid, &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); + 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..5549da7bd7be 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -592,6 +592,6 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, u8 video_code); 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__ */
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.nikula@linux.intel.com> Cc: Ville Syrjala <ville.syrjala@linux.intel.com> Cc: Ankit Nautiyal <ankit.k.nautiyal@intel.com> Cc: intel-gfx <intel-gfx@lists.freedesktop.org> Signed-off-by: Lee Shawn C <shawn.c.lee@intel.com> --- drivers/gpu/drm/drm_connector.c | 8 +++- drivers/gpu/drm/drm_edid.c | 71 +++++++++++++++++++++++++++++++-- include/drm/drm_edid.h | 2 +- 3 files changed, 74 insertions(+), 7 deletions(-)