[Why] When playing HDR or WCG content, bandwidth constraints may force the driver to downgrade to 6bpc, resulting in visual artifacts like banding.
Userspace should be able to configure a minimum allowed bpc. [How] Introduce the "min bpc" connector property so the user can limit the minimum bpc. Mirror the "mac bpc" implementation. Signed-off-by: Sasha McIntosh <[email protected]> --- drivers/gpu/drm/drm_atomic.c | 12 +++++++++ drivers/gpu/drm/drm_atomic_helper.c | 4 +++ drivers/gpu/drm/drm_atomic_uapi.c | 4 +++ drivers/gpu/drm/drm_connector.c | 41 +++++++++++++++++++++++++++++ include/drm/drm_connector.h | 20 ++++++++++++++ 5 files changed, 81 insertions(+) diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index be2cb6e43cb0..f85ad9c55e69 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -468,6 +468,17 @@ static int drm_atomic_connector_check(struct drm_connector *connector, state->max_bpc = info->bpc ? info->bpc : 8; if (connector->max_bpc_property) state->max_bpc = min(state->max_bpc, state->max_requested_bpc); + if (connector->min_bpc_property) + state->min_bpc = state->min_requested_bpc; + if (connector->max_bpc_property && connector->min_bpc_property && + state->max_requested_bpc < state->min_requested_bpc) { + drm_dbg_atomic(connector->dev, + "[CONNECTOR:%d:%s] max bpc %d < min bpc %d\n", + connector->base.id, connector->name, + state->max_requested_bpc, + state->min_requested_bpc); + return -EINVAL; + } if ((connector->connector_type != DRM_MODE_CONNECTOR_WRITEBACK) || !writeback_job) return 0; @@ -1195,6 +1206,7 @@ static void drm_atomic_connector_print_state(struct drm_printer *p, drm_printf(p, "\tinterlace_allowed=%d\n", connector->interlace_allowed); drm_printf(p, "\tycbcr_420_allowed=%d\n", connector->ycbcr_420_allowed); drm_printf(p, "\tmax_requested_bpc=%d\n", state->max_requested_bpc); + drm_printf(p, "\tmin_requested_bpc=%d\n", state->min_requested_bpc); drm_printf(p, "\tcolorspace=%s\n", drm_get_colorspace_name(state->colorspace)); if (connector->connector_type == DRM_MODE_CONNECTOR_HDMIA || diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 5a473a274ff0..75659d46c6fe 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -736,6 +736,10 @@ drm_atomic_helper_check_modeset(struct drm_device *dev, if (old_connector_state->max_requested_bpc != new_connector_state->max_requested_bpc) new_crtc_state->connectors_changed = true; + + if (old_connector_state->min_requested_bpc != + new_connector_state->min_requested_bpc) + new_crtc_state->connectors_changed = true; } if (funcs->atomic_check) diff --git a/drivers/gpu/drm/drm_atomic_uapi.c b/drivers/gpu/drm/drm_atomic_uapi.c index 85dbdaa4a2e2..f99649f9c51f 100644 --- a/drivers/gpu/drm/drm_atomic_uapi.c +++ b/drivers/gpu/drm/drm_atomic_uapi.c @@ -776,6 +776,8 @@ static int drm_atomic_connector_set_property(struct drm_connector *connector, fence_ptr); } else if (property == connector->max_bpc_property) { state->max_requested_bpc = val; + } else if (property == connector->min_bpc_property) { + state->min_requested_bpc = val; } else if (property == connector->privacy_screen_sw_state_property) { state->privacy_screen_sw_state = val; } else if (property == connector->broadcast_rgb_property) { @@ -861,6 +863,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector, *val = 0; } else if (property == connector->max_bpc_property) { *val = state->max_requested_bpc; + } else if (property == connector->min_bpc_property) { + *val = state->min_requested_bpc; } else if (property == connector->privacy_screen_sw_state_property) { *val = state->privacy_screen_sw_state; } else if (property == connector->broadcast_rgb_property) { diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 272d6254ea47..2d9cfd4f5118 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -1699,6 +1699,13 @@ EXPORT_SYMBOL(drm_hdmi_connector_get_output_format_name); * drm_connector_attach_max_bpc_property() to create and attach the * property to the connector during initialization. * + * min bpc: + * This range property is used by userspace to set a lower bound for the bit + * depth. When used the driver would set the bpc in accordance with the + * valid range supported by the hardware and sink. Drivers to use the function + * drm_connector_attach_min_bpc_property() to create and attach the + * property to the connector during initialization. + * * Connectors also have one standardized atomic property: * * CRTC_ID: @@ -2845,6 +2852,40 @@ int drm_connector_attach_max_bpc_property(struct drm_connector *connector, } EXPORT_SYMBOL(drm_connector_attach_max_bpc_property); +/** + * drm_connector_attach_min_bpc_property - attach "min bpc" property + * @connector: connector to attach min bpc property on. + * @min: The minimum bit depth supported by the connector. + * @max: The maximum bit depth supported by the connector. + * + * This is used to add support for limiting the bit depth on a connector. + * + * Returns: + * Zero on success, negative errno on failure. + */ +int drm_connector_attach_min_bpc_property(struct drm_connector *connector, + int min, int max) +{ + struct drm_device *dev = connector->dev; + struct drm_property *prop; + + prop = connector->min_bpc_property; + if (!prop) { + prop = drm_property_create_range(dev, 0, "min bpc", min, max); + if (!prop) + return -ENOMEM; + + connector->min_bpc_property = prop; + } + + drm_object_attach_property(&connector->base, prop, min); + connector->state->min_requested_bpc = min; + connector->state->min_bpc = min; + + return 0; +} +EXPORT_SYMBOL(drm_connector_attach_min_bpc_property); + /** * drm_connector_attach_hdr_output_metadata_property - attach "HDR_OUTPUT_METADA" property * @connector: connector to attach the property on. diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 8f34f4b8183d..7581f965b015 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -1126,12 +1126,24 @@ struct drm_connector_state { */ u8 max_requested_bpc; + /** + * @min_requested_bpc: Connector property to limit the minimum bit + * depth of the pixels. + */ + u8 min_requested_bpc; + /** * @max_bpc: Connector max_bpc based on the requested max_bpc property * and the connector bpc limitations obtained from edid. */ u8 max_bpc; + /** + * @min_bpc: Connector min_bpc based on the requested min_bpc property + * and the connector bpc limitations obtained from edid. + */ + u8 min_bpc; + /** * @privacy_screen_sw_state: See :ref:`Standard Connector * Properties<standard_connector_properties>` @@ -2079,6 +2091,12 @@ struct drm_connector { */ struct drm_property *max_bpc_property; + /** + * @min_bpc_property: Default connector property for the min bpc to be + * driven out of the connector. + */ + struct drm_property *min_bpc_property; + /** @privacy_screen: drm_privacy_screen for this connector, or NULL. */ struct drm_privacy_screen *privacy_screen; @@ -2482,6 +2500,8 @@ int drm_connector_set_orientation_from_panel( struct drm_panel *panel); int drm_connector_attach_max_bpc_property(struct drm_connector *connector, int min, int max); +int drm_connector_attach_min_bpc_property(struct drm_connector *connector, + int min, int max); void drm_connector_create_privacy_screen_properties(struct drm_connector *conn); void drm_connector_attach_privacy_screen_properties(struct drm_connector *conn); void drm_connector_attach_privacy_screen_provider( base-commit: 098456f3141bf9e0c0d8973695ca38a03465ccd6 -- 2.51.1.851.g4ebd6896fd-goog
