| Message ID | 20220426123044.320415-2-jouni.hogander@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | HDR aux backlight range calculation | expand |
On Tue, 26 Apr 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. IMO all of this should be computed at EDID parsing time once and stored in the metadata. Maybe in drm_parse_hdr_metadata_block(). Over time we've added a bunch of functions to do this type of stuff, and all drivers call them at slightly different times and different ways, and it just grows complicated. (Also, I think basically everything that comes out of the EDID or DisplayID should be stored in connector->display_info instead of being spread around like we currently do. But that's for another patch series, another time.) BR, Jani. > > 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> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com> > --- > drivers/gpu/drm/drm_edid.c | 55 ++++++++++++++++++++++++++++++++++++++ > include/drm/drm_edid.h | 4 +++ > 2 files changed, 59 insertions(+) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 7a8482b75071..1cb886debbbe 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -4005,6 +4005,61 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, > } > EXPORT_SYMBOL(drm_display_mode_from_cea_vic); > > +/** > + * drm_luminance_range_from_static_hdr_metadata() - luminance range from static hdr > + * metadata > + * @connector: connector we're calculating for > + * @min: Calculated min value > + * @max: Calculated max value > + * > + * Calculates backlight min and max as described in CTA-861-G > + * > + * Returns: True when calculation succeeds. > + */ > +bool > +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, > + u32 *min, u32 *max) > +{ > + struct hdr_sink_metadata *hdr_metadata = &connector->hdr_sink_metadata; > + 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 min_cll, max_cll, q, r; > + > + if (!(hdr_metadata->hdmi_type1.metadata_type & > + BIT(HDMI_STATIC_METADATA_TYPE1))) > + return false; > + > + max_cll = hdr_metadata->hdmi_type1.max_cll; > + min_cll = hdr_metadata->hdmi_type1.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_cll >> 5; > + r = max_cll % 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); > + > + return true; > +} > +EXPORT_SYMBOL(drm_luminance_range_from_static_hdr_metadata); > + > static int > do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len) > { > diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h > index c3204a58fb09..63e441c84d72 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -406,6 +406,10 @@ drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame, > const struct drm_display_mode *mode, > enum hdmi_quantization_range rgb_quant_range); > > +bool > +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, > + u32 *min, u32 *max); > + > /** > * drm_eld_mnl - Get ELD monitor name length in bytes. > * @eld: pointer to an eld memory structure with mnl set
Yes I agree that this data parsed from EDID/Display ID should be stored in structs defined in drm_display_info. Like for the VRR range that we parse from EDID, we store that in a struct monitor_range in drm_display_info. Manasi -----Original Message----- From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of Jani Nikula Sent: Tuesday, April 26, 2022 6:38 AM To: Hogander, Jouni <jouni.hogander@intel.com>; dri-devel@lists.freedesktop.org Cc: Hogander, Jouni <jouni.hogander@intel.com>; Rodrigo Siqueira <Rodrigo.Siqueira@amd.com>; Kahola, Mika <mika.kahola@intel.com> Subject: Re: [PATCH 1/3] drm: New function to get luminance range based on static hdr metadata On Tue, 26 Apr 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. IMO all of this should be computed at EDID parsing time once and stored in the metadata. Maybe in drm_parse_hdr_metadata_block(). Over time we've added a bunch of functions to do this type of stuff, and all drivers call them at slightly different times and different ways, and it just grows complicated. (Also, I think basically everything that comes out of the EDID or DisplayID should be stored in connector->display_info instead of being spread around like we currently do. But that's for another patch series, another time.) BR, Jani. > > 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> > Signed-off-by: Jouni Högander <jouni.hogander@intel.com> > --- > drivers/gpu/drm/drm_edid.c | 55 ++++++++++++++++++++++++++++++++++++++ > include/drm/drm_edid.h | 4 +++ > 2 files changed, 59 insertions(+) > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > index 7a8482b75071..1cb886debbbe 100644 > --- a/drivers/gpu/drm/drm_edid.c > +++ b/drivers/gpu/drm/drm_edid.c > @@ -4005,6 +4005,61 @@ drm_display_mode_from_cea_vic(struct drm_device > *dev, } EXPORT_SYMBOL(drm_display_mode_from_cea_vic); > > +/** > + * drm_luminance_range_from_static_hdr_metadata() - luminance range > +from static hdr > + * metadata > + * @connector: connector we're calculating for > + * @min: Calculated min value > + * @max: Calculated max value > + * > + * Calculates backlight min and max as described in CTA-861-G > + * > + * Returns: True when calculation succeeds. > + */ > +bool > +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, > + u32 *min, u32 *max) > +{ > + struct hdr_sink_metadata *hdr_metadata = &connector->hdr_sink_metadata; > + 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 min_cll, max_cll, q, r; > + > + if (!(hdr_metadata->hdmi_type1.metadata_type & > + BIT(HDMI_STATIC_METADATA_TYPE1))) > + return false; > + > + max_cll = hdr_metadata->hdmi_type1.max_cll; > + min_cll = hdr_metadata->hdmi_type1.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_cll >> 5; > + r = max_cll % 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); > + > + return true; > +} > +EXPORT_SYMBOL(drm_luminance_range_from_static_hdr_metadata); > + > static int > do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len) > { diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index > c3204a58fb09..63e441c84d72 100644 > --- a/include/drm/drm_edid.h > +++ b/include/drm/drm_edid.h > @@ -406,6 +406,10 @@ drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame, > const struct drm_display_mode *mode, > enum hdmi_quantization_range rgb_quant_range); > > +bool > +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, > + u32 *min, u32 *max); > + > /** > * drm_eld_mnl - Get ELD monitor name length in bytes. > * @eld: pointer to an eld memory structure with mnl set -- Jani Nikula, Intel Open Source Graphics Center
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index 7a8482b75071..1cb886debbbe 100644 --- a/drivers/gpu/drm/drm_edid.c +++ b/drivers/gpu/drm/drm_edid.c @@ -4005,6 +4005,61 @@ drm_display_mode_from_cea_vic(struct drm_device *dev, } EXPORT_SYMBOL(drm_display_mode_from_cea_vic); +/** + * drm_luminance_range_from_static_hdr_metadata() - luminance range from static hdr + * metadata + * @connector: connector we're calculating for + * @min: Calculated min value + * @max: Calculated max value + * + * Calculates backlight min and max as described in CTA-861-G + * + * Returns: True when calculation succeeds. + */ +bool +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, + u32 *min, u32 *max) +{ + struct hdr_sink_metadata *hdr_metadata = &connector->hdr_sink_metadata; + 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 min_cll, max_cll, q, r; + + if (!(hdr_metadata->hdmi_type1.metadata_type & + BIT(HDMI_STATIC_METADATA_TYPE1))) + return false; + + max_cll = hdr_metadata->hdmi_type1.max_cll; + min_cll = hdr_metadata->hdmi_type1.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_cll >> 5; + r = max_cll % 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); + + return true; +} +EXPORT_SYMBOL(drm_luminance_range_from_static_hdr_metadata); + static int do_cea_modes(struct drm_connector *connector, const u8 *db, u8 len) { diff --git a/include/drm/drm_edid.h b/include/drm/drm_edid.h index c3204a58fb09..63e441c84d72 100644 --- a/include/drm/drm_edid.h +++ b/include/drm/drm_edid.h @@ -406,6 +406,10 @@ drm_hdmi_avi_infoframe_quant_range(struct hdmi_avi_infoframe *frame, const struct drm_display_mode *mode, enum hdmi_quantization_range rgb_quant_range); +bool +drm_luminance_range_from_static_hdr_metadata(struct drm_connector *connector, + u32 *min, u32 *max); + /** * drm_eld_mnl - Get ELD monitor name length in bytes. * @eld: pointer to an eld memory structure with mnl set
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. 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> Signed-off-by: Jouni Högander <jouni.hogander@intel.com> --- drivers/gpu/drm/drm_edid.c | 55 ++++++++++++++++++++++++++++++++++++++ include/drm/drm_edid.h | 4 +++ 2 files changed, 59 insertions(+)