| Message ID | 20220620072019.2710652-3-jouni.hogander@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | HDR aux backlight range calculation | expand |
On Mon, 20 Jun 2022, Jouni Högander <jouni.hogander@intel.com> wrote: > Split luminance min/max calculation using static hdr metadata from > drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:update_connector_ext_caps > into drm/drm_edid.c and use it during edid parsing. Calculated range is > stored into connector->display_info->luminance_range. > > v2: Calculate range during edid parsing > > Cc: Roman Li <roman.li@amd.com> > Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> > Cc: Harry Wentland <harry.wentland@amd.com> > Cc: Lyude Paul <lyude@redhat.com> > Cc: Mika Kahola <mika.kahola@intel.com> > Cc: Jani Nikula <jani.nikula@intel.com> > Cc: Manasi Navare <manasi.d.navare@intel.com> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com> > --- > drivers/gpu/drm/drm_edid.c | 50 +++++++++++++++++++++++++++++++++++++- > 1 file changed, 49 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 2bdaf1e34a9d..3b367100290f 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -5014,6 +5014,49 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode) > mode->clock = clock; > } > > +static void drm_calculate_luminance_range(struct drm_connector *connector) > +{ > + struct hdr_static_metadata *hdr_metadata = &connector->hdr_sink_metadata.hdmi_type1; > + struct drm_luminance_range_info *luminance_range = > + &connector->display_info.luminance_range; > + static const u8 pre_computed_values[] = { > + 50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 65, 66, 68, 69, > + 71, 72, 74, 75, 77, 79, 81, 82, 84, 86, 88, 90, 92, 94, 96, 98}; Nitpick, newline before }; > + u32 max_avg, min_cll, max, min, q, r; > + > + if (!(hdr_metadata->metadata_type & BIT(HDMI_STATIC_METADATA_TYPE1))) > + return; > + > + max_avg = hdr_metadata->max_fall; > + min_cll = hdr_metadata->min_cll; > + > + /* From the specification (CTA-861-G), for calculating the maximum Nitpick, newline after /*. > + * luminance we need to use: > + * Luminance = 50*2**(CV/32) > + * Where CV is a one-byte value. > + * For calculating this expression we may need float point precision; > + * to avoid this complexity level, we take advantage that CV is divided > + * by a constant. From the Euclids division algorithm, we know that CV > + * can be written as: CV = 32*q + r. Next, we replace CV in the > + * Luminance expression and get 50*(2**q)*(2**(r/32)), hence we just > + * need to pre-compute the value of r/32. For pre-computing the values > + * We just used the following Ruby line: > + * (0...32).each {|cv| puts (50*2**(cv/32.0)).round} > + * The results of the above expressions can be verified at > + * pre_computed_values. > + */ > + q = max_avg >> 5; > + r = max_avg % 32; > + max = (1 << q) * pre_computed_values[r]; > + > + /* min luminance: maxLum * (CV/255)^2 / 100 */ > + q = DIV_ROUND_CLOSEST(min_cll, 255); > + min = max * DIV_ROUND_CLOSEST((q * q), 100); > + > + luminance_range->min_luminance = min; > + luminance_range->max_luminance = max; I'll just trust this; not going to start verifying. Acked-by: Jani Nikula <jani.nikula@intel.com> > +} > + > static uint8_t eotf_supported(const u8 *edid_ext) > { > return edid_ext[2] & > @@ -5045,8 +5088,12 @@ drm_parse_hdr_metadata_block(struct drm_connector *connector, const u8 *db) > connector->hdr_sink_metadata.hdmi_type1.max_cll = db[4]; > if (len >= 5) > connector->hdr_sink_metadata.hdmi_type1.max_fall = db[5]; > - if (len >= 6) > + if (len >= 6) { > connector->hdr_sink_metadata.hdmi_type1.min_cll = db[6]; > + > + /* Calculate only when all values are available */ > + drm_calculate_luminance_range(connector); > + } > } > > static void > @@ -5951,6 +5998,7 @@ drm_reset_display_info(struct drm_connector *connector) > > info->non_desktop = 0; > memset(&info->monitor_range, 0, sizeof(info->monitor_range)); > + memset(&info->luminance_range, 0, sizeof(info->luminance_range)); > > info->mso_stream_count = 0; > info->mso_pixel_overlap = 0;
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 2bdaf1e34a9d..3b367100290f 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -5014,6 +5014,49 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode) mode->clock = clock; } +static void drm_calculate_luminance_range(struct drm_connector *connector) +{ + struct hdr_static_metadata *hdr_metadata = &connector->hdr_sink_metadata.hdmi_type1; + struct drm_luminance_range_info *luminance_range = + &connector->display_info.luminance_range; + static const u8 pre_computed_values[] = { + 50, 51, 52, 53, 55, 56, 57, 58, 59, 61, 62, 63, 65, 66, 68, 69, + 71, 72, 74, 75, 77, 79, 81, 82, 84, 86, 88, 90, 92, 94, 96, 98}; + u32 max_avg, min_cll, max, min, q, r; + + if (!(hdr_metadata->metadata_type & BIT(HDMI_STATIC_METADATA_TYPE1))) + return; + + max_avg = hdr_metadata->max_fall; + min_cll = hdr_metadata->min_cll; + + /* From the specification (CTA-861-G), for calculating the maximum + * luminance we need to use: + * Luminance = 50*2**(CV/32) + * Where CV is a one-byte value. + * For calculating this expression we may need float point precision; + * to avoid this complexity level, we take advantage that CV is divided + * by a constant. From the Euclids division algorithm, we know that CV + * can be written as: CV = 32*q + r. Next, we replace CV in the + * Luminance expression and get 50*(2**q)*(2**(r/32)), hence we just + * need to pre-compute the value of r/32. For pre-computing the values + * We just used the following Ruby line: + * (0...32).each {|cv| puts (50*2**(cv/32.0)).round} + * The results of the above expressions can be verified at + * pre_computed_values. + */ + q = max_avg >> 5; + r = max_avg % 32; + max = (1 << q) * pre_computed_values[r]; + + /* min luminance: maxLum * (CV/255)^2 / 100 */ + q = DIV_ROUND_CLOSEST(min_cll, 255); + min = max * DIV_ROUND_CLOSEST((q * q), 100); + + luminance_range->min_luminance = min; + luminance_range->max_luminance = max; +} + static uint8_t eotf_supported(const u8 *edid_ext) { return edid_ext[2] & @@ -5045,8 +5088,12 @@ drm_parse_hdr_metadata_block(struct drm_connector *connector, const u8 *db) connector->hdr_sink_metadata.hdmi_type1.max_cll = db[4]; if (len >= 5) connector->hdr_sink_metadata.hdmi_type1.max_fall = db[5]; - if (len >= 6) + if (len >= 6) { connector->hdr_sink_metadata.hdmi_type1.min_cll = db[6]; + + /* Calculate only when all values are available */ + drm_calculate_luminance_range(connector); + } } static void @@ -5951,6 +5998,7 @@ drm_reset_display_info(struct drm_connector *connector) info->non_desktop = 0; memset(&info->monitor_range, 0, sizeof(info->monitor_range)); + memset(&info->luminance_range, 0, sizeof(info->luminance_range)); info->mso_stream_count = 0; info->mso_pixel_overlap = 0;
Split luminance min/max calculation using static hdr metadata from drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c:update_connector_ext_caps into drm/drm_edid.c and use it during edid parsing. Calculated range is stored into connector->display_info->luminance_range. v2: Calculate range during edid parsing Cc: Roman Li <roman.li@amd.com> Cc: Rodrigo Siqueira <Rodrigo.Siqueira@amd.com> Cc: Harry Wentland <harry.wentland@amd.com> Cc: Lyude Paul <lyude@redhat.com> Cc: Mika Kahola <mika.kahola@intel.com> Cc: Jani Nikula <jani.nikula@intel.com> Cc: Manasi Navare <manasi.d.navare@intel.com> Signed-off-by: Jouni Högander <jouni.hogander@intel.com> --- drivers/gpu/drm/drm_edid.c | 50 +++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-)