Re: [PATCH RFC v2 05/37] drm/connector: hdmi: Add output BPC to the connector state
From: Jani Nikula
Date: Thu Sep 21 2023 - 17:20:48 EST
On Thu, 21 Sep 2023, Pekka Paalanen <ppaalanen@xxxxxxxxx> wrote:
> On Wed, 20 Sep 2023 16:35:20 +0200
> Maxime Ripard <mripard@xxxxxxxxxx> wrote:
>
>> We'll add automatic selection of the output BPC in a following patch,
>> but let's add it to the HDMI connector state already.
>>
>> Signed-off-by: Maxime Ripard <mripard@xxxxxxxxxx>
>> ---
>> drivers/gpu/drm/drm_atomic.c | 4 +++-
>> drivers/gpu/drm/drm_atomic_state_helper.c | 6 +++++-
>> drivers/gpu/drm/drm_connector.c | 13 ++++++++++++-
>> include/drm/drm_connector.h | 13 ++++++++++++-
>> 4 files changed, 32 insertions(+), 4 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c
>> index b1b56dcaa76b..8dce0a2f2ac3 100644
>> --- a/drivers/gpu/drm/drm_atomic.c
>> +++ b/drivers/gpu/drm/drm_atomic.c
>> @@ -1143,9 +1143,11 @@ static void drm_atomic_connector_print_state(struct drm_printer *p,
>> drm_printf(p, "\tcolorspace=%s\n", drm_get_colorspace_name(state->colorspace));
>>
>> if (connector->connector_type == DRM_MODE_CONNECTOR_HDMIA ||
>> - connector->connector_type == DRM_MODE_CONNECTOR_HDMIB)
>> + connector->connector_type == DRM_MODE_CONNECTOR_HDMIB) {
>> drm_printf(p, "\tbroadcast_rgb=%s\n",
>> drm_hdmi_connector_get_broadcast_rgb_name(state->hdmi.broadcast_rgb));
>> + drm_printf(p, "\toutput_bpc=%u\n", state->hdmi.output_bpc);
>> + }
>>
>> if (connector->connector_type == DRM_MODE_CONNECTOR_WRITEBACK)
>> if (state->writeback_job && state->writeback_job->fb)
>> diff --git a/drivers/gpu/drm/drm_atomic_state_helper.c b/drivers/gpu/drm/drm_atomic_state_helper.c
>> index 0f7e5ba555b8..2c9b52ae1b56 100644
>> --- a/drivers/gpu/drm/drm_atomic_state_helper.c
>> +++ b/drivers/gpu/drm/drm_atomic_state_helper.c
>> @@ -569,6 +569,9 @@ EXPORT_SYMBOL(drm_atomic_helper_connector_tv_reset);
>> void __drm_atomic_helper_connector_hdmi_reset(struct drm_connector *connector,
>> struct drm_connector_state *new_state)
>> {
>> + new_state->max_bpc = 8;
>> + new_state->max_requested_bpc = 8;
>> + new_state->hdmi.output_bpc = 8;
>
> Hi,
>
> will this be forcing all drivers using these helpers to default to max bpc = 8?
>
> I believe at least amdgpu would disagree. The defaults were changed in
> the recent years, IIRC to avoid extra modesets during boot-up when
> desktops prefer highest possible bpc for a mode.
>
> The 'max bpc' property itself is a manual workaround for faulty
> hardware that does not correctly indicate the max bpc it can handle. It
> should not default to be a limiting factor.
>
>> new_state->hdmi.broadcast_rgb = DRM_HDMI_BROADCAST_RGB_AUTO;
>> }
>> EXPORT_SYMBOL(__drm_atomic_helper_connector_hdmi_reset);
>> @@ -651,7 +654,8 @@ int drm_atomic_helper_connector_hdmi_check(struct drm_connector *connector,
>> struct drm_connector_state *new_state =
>> drm_atomic_get_new_connector_state(state, connector);
>>
>> - if (old_state->hdmi.broadcast_rgb != new_state->hdmi.broadcast_rgb) {
>> + if (old_state->hdmi.broadcast_rgb != new_state->hdmi.broadcast_rgb ||
>> + old_state->hdmi.output_bpc != new_state->hdmi.output_bpc) {
>> struct drm_crtc *crtc = new_state->crtc;
>> struct drm_crtc_state *crtc_state;
>>
>> diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c
>> index b45471d540ac..f55f5918411c 100644
>> --- a/drivers/gpu/drm/drm_connector.c
>> +++ b/drivers/gpu/drm/drm_connector.c
>> @@ -459,6 +459,7 @@ EXPORT_SYMBOL(drmm_connector_init);
>> * @funcs: callbacks for this connector
>> * @connector_type: user visible type of the connector
>> * @ddc: optional pointer to the associated ddc adapter
>> + * @max_bpc: Maximum bits per char the HDMI connector supports
>> *
>> * Initialises a preallocated HDMI connector. Connectors can be
>> * subclassed as part of driver connector objects.
>> @@ -475,7 +476,8 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>> struct drm_connector *connector,
>> const struct drm_connector_funcs *funcs,
>> int connector_type,
>> - struct i2c_adapter *ddc)
>> + struct i2c_adapter *ddc,
>> + unsigned int max_bpc)
>> {
>> int ret;
>>
>> @@ -487,6 +489,15 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>> if (ret)
>> return ret;
>>
>> + if (max_bpc) {
>> + if (!(max_bpc == 8 || max_bpc == 10 || max_bpc == 12))
>> + return -EINVAL;
>> +
>> + drm_connector_attach_hdr_output_metadata_property(connector);
>> + drm_connector_attach_max_bpc_property(connector, 8, max_bpc);
>> + connector->max_bpc = max_bpc;
>> + }
>> +
>> return 0;
>> }
>> EXPORT_SYMBOL(drmm_connector_hdmi_init);
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index fdcf64ab91a9..d0bcb835c857 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -1056,6 +1056,11 @@ struct drm_connector_state {
>> * Broadcast RGB selection value.
>> */
>> enum drm_hdmi_broadcast_rgb broadcast_rgb;
>> +
>> + /**
>> + * @output_bpc: Bits per character to output.
>
> Is it not bits per channel?
Or component. Or color. Or color channel. ;)
But character I've never heard.
BR,
Jani.
>
>> + */
>> + unsigned int output_bpc;
>> } hdmi;
>> };
>>
>> @@ -1700,6 +1705,11 @@ struct drm_connector {
>> */
>> struct drm_property_blob *path_blob_ptr;
>>
>> + /**
>> + * @max_bpc: Maximum bits per character the connector supports.
>
> channel?
>
>> + */
>> + unsigned int max_bpc;
>> +
>> /**
>> * @max_bpc_property: Default connector property for the max bpc to be
>> * driven out of the connector.
>> @@ -1939,7 +1949,8 @@ int drmm_connector_hdmi_init(struct drm_device *dev,
>> struct drm_connector *connector,
>> const struct drm_connector_funcs *funcs,
>> int connector_type,
>> - struct i2c_adapter *ddc);
>> + struct i2c_adapter *ddc,
>> + unsigned int max_bpc);
>> void drm_connector_attach_edid_property(struct drm_connector *connector);
>> int drm_connector_register(struct drm_connector *connector);
>> void drm_connector_unregister(struct drm_connector *connector);
>>
>
> Thanks,
> pq
--
Jani Nikula, Intel