On Mon, Dec 05, 2016 at 08:57:43AM +0100, Thierry Reding wrote: > On Sat, Dec 03, 2016 at 04:35:24AM +0000, Sharma, Shashank wrote: > > Hi Thierry, > > > > If you can please have a look on this patch, I had written one to parse > > HF-VSDB, which was covering SCDC detection too. > > https://patchwork.kernel.org/patch/9452259/ > > I think there had been pushback before about caching capabilities from > EDID, so from that point of view my patch is more inline with existing > EDID parsing API.
Hm, where was that pushback? We do have a bit a mess between explicitly parsing stuff (e.g. eld) and stuffing parsed data into drm_display_info. I think long-term stuffing it into drm_display_info is probably better, since then we only have 1 interaction point between the probe code and the atomic_check code. That should be useful for eventually fixing the lack of locking between the two, if I ever get around to that ;-) > Other than that the patches are mostly equivalent, except yours parses > more information than just the SCDC bits. So merge patch 1 from your series + Shashank's parsing patch? Everyone agrees and can you pls cross-r-b stamp so I can apply it all? Thanks, Daniel > > Thierry > > > -----Original Message----- > > From: Thierry Reding [mailto:thierry.reding at gmail.com] > > Sent: Saturday, December 3, 2016 12:54 AM > > To: dri-devel at lists.freedesktop.org > > Cc: Jani Nikula <jani.nikula at linux.intel.com>; Sharma, Shashank > > <shashank.sharma at intel.com>; Ville Syrjälä <ville.syrjala at > > linux.intel.com>; Jose Abreu <joabreu at synopsys.com> > > Subject: [PATCH v2 2/3] drm/edid: Implement SCDC support detection > > > > From: Thierry Reding <treding at nvidia.com> > > > > Sinks compliant with the HDMI 2.0 specification may support SCDC, a > > mechanism for the source and the sink to communicate. Sinks advertise > > support for this feature in the HDMI Forum Vendor Specific Data Block as > > defined in the HDMI 2.0 specification, section 10.4 "Status and Control > > Data Channel". Implement a small helper that find the HF-VSDB and parses it > > to check if the sink supports SCDC. > > > > Signed-off-by: Thierry Reding <treding at nvidia.com> > > --- > > Changes in v2: > > - rename internal function to cea_db_is_hdmi_forum_vsdb() for more > > clarity (Ville Syrjälä) > > > > drivers/gpu/drm/drm_edid.c | 49 > > ++++++++++++++++++++++++++++++++++++++++++++++ > > include/drm/drm_edid.h | 1 + > > include/linux/hdmi.h | 1 + > > 3 files changed, 51 insertions(+) > > > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index > > 336be31ff3de..369961597ee5 100644 > > --- a/drivers/gpu/drm/drm_edid.c > > +++ b/drivers/gpu/drm/drm_edid.c > > @@ -3238,6 +3238,21 @@ static bool cea_db_is_hdmi_vsdb(const u8 *db) > > return hdmi_id == HDMI_IEEE_OUI; > > } > > > > +static bool cea_db_is_hdmi_forum_vsdb(const u8 *db) { > > + unsigned int oui; > > + > > + if (cea_db_tag(db) != VENDOR_BLOCK) > > + return false; > > + > > + if (cea_db_payload_len(db) < 7) > > + return false; > > + > > + oui = db[3] << 16 | db[2] << 8 | db[1]; > > + > > + return oui == HDMI_FORUM_IEEE_OUI; > > +} > > + > > #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) > > > > @@ -3687,6 +3702,40 @@ bool drm_detect_hdmi_monitor(struct edid *edid) > > EXPORT_SYMBOL(drm_detect_hdmi_monitor); > > > > /** > > + * drm_detect_hdmi_scdc - detect whether an HDMI sink supports SCDC > > + * @edid: sink EDID information > > + * > > + * Parse the CEA extension according to CEA-861-B to find an HF-VSDB as > > + * defined in HDMI 2.0, section 10.3.2 "HDMI Forum Vendor Specific Data > > + * Block" and checks if the SCDC_Present bit (bit 7 of byte 6) is set. > > + * > > + * Returns: > > + * True if the sink supports SCDC, false otherwise. > > + */ > > +bool drm_detect_hdmi_scdc(struct edid *edid) { > > + unsigned int start, end, i; > > + const u8 *cea; > > + > > + cea = drm_find_cea_extension(edid); > > + if (!cea) > > + return false; > > + > > + if (cea_db_offsets(cea, &start, &end)) > > + return false; > > + > > + for_each_cea_db(cea, i, start, end) { > > + if (cea_db_is_hdmi_forum_vsdb(&cea[i])) { > > + if (cea[i + 6] & 0x80) > > + return true; > > + } > > + } > > + > > + return false; > > +} > > +EXPORT_SYMBOL(drm_detect_hdmi_scdc); > > + > > +/** > > * drm_detect_monitor_audio - check monitor audio capability > > * @edid: EDID block to scan > > * > > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index > > 38eabf65f19d..7ea7e90846d8 100644 > > --- a/include/drm/drm_edid.h > > +++ b/include/drm/drm_edid.h > > @@ -440,6 +440,7 @@ int drm_add_edid_modes(struct drm_connector *connector, > > struct edid *edid); > > u8 drm_match_cea_mode(const struct drm_display_mode *to_match); enum > > hdmi_picture_aspect drm_get_cea_aspect_ratio(const u8 video_code); bool > > drm_detect_hdmi_monitor(struct edid *edid); > > +bool drm_detect_hdmi_scdc(struct edid *edid); > > bool drm_detect_monitor_audio(struct edid *edid); bool > > drm_rgb_quant_range_selectable(struct edid *edid); int > > drm_add_modes_noedid(struct drm_connector *connector, diff --git > > a/include/linux/hdmi.h b/include/linux/hdmi.h index > > edbb4fc674ed..d271ff23984f 100644 > > --- a/include/linux/hdmi.h > > +++ b/include/linux/hdmi.h > > @@ -35,6 +35,7 @@ enum hdmi_infoframe_type { }; > > > > #define HDMI_IEEE_OUI 0x000c03 > > +#define HDMI_FORUM_IEEE_OUI 0xc45dd8 > > #define HDMI_INFOFRAME_HEADER_SIZE 4 > > #define HDMI_AVI_INFOFRAME_SIZE 13 > > #define HDMI_SPD_INFOFRAME_SIZE 25 > > -- > > 2.10.2 > > > _______________________________________________ > dri-devel mailing list > dri-devel at lists.freedesktop.org > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
