Re: [PATCH v5 7/7] drm: create hdmi output property

Regards

Shashank

On 6/27/2017 5:44 PM, Ville Syrjälä wrote:

On Wed, Jun 21, 2017 at 04:04:13PM +0530, Shashank Sharma wrote:

...

HDMI displays can support various output types, based on the color space and subsampling type. The possible outputs from a HDMI 2.0 monitor could be:

• RGB
• YCBCR 444
• YCBCR 422
• YCBCR 420

This patch adds a drm property "hdmi_output_format", using which, a user can specify its preference, for the HDMI output type. The output type enums are similar to the mentioned outputs above. To handle various subsampling of YCBCR output types, this property allows two special cases:

• DRM_HDMI_OUTPUT_YCBCR_HQ This indicates preferred output should be YCBCR output, with highest subsampling rate by the source/sink, which can be typically:
• ycbcr444
• ycbcr422
• ycbcr420
• DRM_HDMI_OUTPUT_YCBCR_LQ This indicates preferred output should be YCBCR output, with lowest subsampling rate supported by source/sink, which can be:
• ycbcr420
• ycbcr422
• ycbcr444

I think we'll eventually need something more thorough than this to allow full control over the AVI infoframe/MSA MISC/VSC SDP colormietry stuff.

So I think we need to control at least these things:

• max bpc (some people seem to have some real needs to avoid deep color)
• rgb->ycbcr conversion (yes/no)
• ycbcr subsampling for the conversion and infoframe
• ycbcr encoding for the conversion and infoframe
• infoframe colorimetry

I've not really figured out how we'll tie all that together in a way that doesn't get super confusing.

I think we will over complicate stuff, if we try to address everything in this same series. My high level vision for the work was: - Let this series just deals with HDMI output, and handles the output color model only, using the AVI IF (which is being handled already in the next patch) - The BT2020 patch series will (should) take care of everything which is related to output color spaces (including AVI IF) As this series deals with stuff which comes into picture post blending, it should focus on just the output color model and sub-sampling, which its doing using the HDMI_OUTPUT property introduced. But at the same time I agree, that max_bpc is something we should introduce at the DRM level, instead of keeping it at driver level.

One idea might be that the infoframe stuff is totally independent of the rest (ie. we'll define just an enum property for the infoframe stuff in say this way: "Automatic", "sRGB", "AdobeRGB", "YCbCr BT.601 4:2:2", "xvYCC709 4:4:4", etc. So none of the YCbCr output properties would actually affect the infoframe unless the user has selected the default "Automatic" mode. That should allow the user to output any kind of data through the pipe in a pass through fashion (or with manually set up gamma/degamma/csc). And configuring the inforame property would not affect the data passing through the pipe in any way.

But I probably need to think more about this. So for now I think I'll just want to get the automagic "use YCbCr 4:2:0 if we must" thing working without any new properties getting in the way. We just have to keep in mind that this automagic conversion thing must still work when we add some properties, but I think that can generally be achieved with some "Automatic" default property values.

Ok, I think I am getting the bigger picture now. Yes, I agree, it would be pretty cool to have something like this, which makes pipe completely independent in terms of what it can produce vs what it is informing via IF. But need to really sit and think about this well.

- Shashank

...

Default value of the property is set to 0 = RGB, so no changes if you dont set the property.

PS: While doing modeset for YCBCR 420 only modes, this property is ignored, as those timings can be supported only in YCBCR 420 output mode.

V2: Added description for the new variable to address build warning V3: Rebase V4: Rebase V5: Added get_property counterpart to fix IGT BAT failures

Cc: Ville Syrjala ville.syrjala@linux.intel.com Cc: Jose Abreu joabreu@synopsys.com Cc: Daniel Vetter daniel.vetter@intel.com Signed-off-by: Shashank Sharma shashank.sharma@intel.com

---

drivers/gpu/drm/drm_atomic.c | 4 ++++ drivers/gpu/drm/drm_atomic_helper.c | 4 ++++ drivers/gpu/drm/drm_connector.c | 32 ++++++++++++++++++++++++++++++++ include/drm/drm_connector.h | 18 ++++++++++++++++++ include/drm/drm_mode_config.h | 5 +++++ 5 files changed, 63 insertions(+)

diff --git a/drivers/gpu/drm/drm_atomic.c b/drivers/gpu/drm/drm_atomic.c index 77dcef0..ea90f8e 100644 --- a/drivers/gpu/drm/drm_atomic.c +++ b/drivers/gpu/drm/drm_atomic.c @@ -1192,6 +1192,8 @@ int drm_atomic_connector_set_property(struct drm_connector *connector, state->picture_aspect_ratio = val; } else if (property == connector->scaling_mode_property) { state->scaling_mode = val;

• } else if (property == config->hdmi_output_property) {

• state->hdmi_output = val;
  

  } else if (connector->funcs->atomic_set_property) { return connector->funcs->atomic_set_property(connector, state, property, val);

@@ -1272,6 +1274,8 @@ drm_atomic_connector_get_property(struct drm_connector *connector, *val = state->picture_aspect_ratio; } else if (property == connector->scaling_mode_property) { *val = state->scaling_mode;

• } else if (property == config->hdmi_output_property) {

• *val = state->hdmi_output;
  

  } else if (connector->funcs->atomic_get_property) { return connector->funcs->atomic_get_property(connector, state, property, val);

diff --git a/drivers/gpu/drm/drm_atomic_helper.c b/drivers/gpu/drm/drm_atomic_helper.c index 86d3093..1356b3f 100644 --- a/drivers/gpu/drm/drm_atomic_helper.c +++ b/drivers/gpu/drm/drm_atomic_helper.c @@ -637,6 +637,10 @@ drm_atomic_helper_check_modeset(struct drm_device *dev, if (old_connector_state->link_status != new_connector_state->link_status) new_crtc_state->connectors_changed = true;

• 	if (old_connector_state->hdmi_output !=
  

• 	    new_connector_state->hdmi_output)
  

• 		new_crtc_state->connectors_changed = true;
  

  }

  if (funcs->atomic_check)

diff --git a/drivers/gpu/drm/drm_connector.c b/drivers/gpu/drm/drm_connector.c index 5cd61af..f3c5928 100644 --- a/drivers/gpu/drm/drm_connector.c +++ b/drivers/gpu/drm/drm_connector.c @@ -227,6 +227,11 @@ int drm_connector_init(struct drm_device *dev, config->edid_property, 0);

• if (connector_type != DRM_MODE_CONNECTOR_VIRTUAL)

• drm_object_attach_property(&connector->base,
  

• 			   config->hdmi_output_property,
  

• 			   0);
  

• drm_object_attach_property(&connector->base, config->dpms_property, 0);

@@ -617,6 +622,26 @@ static const struct drm_prop_enum_list drm_link_status_enum_list[] = { }; DRM_ENUM_NAME_FN(drm_get_link_status_name, drm_link_status_enum_list)

+static const struct drm_prop_enum_list drm_hdmi_output_enum_list[] = {

• { DRM_HDMI_OUTPUT_DEFAULT_RGB, "output_rgb" },
• { DRM_HDMI_OUTPUT_YCBCR444, "output_ycbcr444" },
• { DRM_HDMI_OUTPUT_YCBCR422, "output_ycbcr422" },
• { DRM_HDMI_OUTPUT_YCBCR420, "output_ycbcr420" },
• { DRM_HDMI_OUTPUT_YCBCR_HQ, "output_ycbcr_high_subsampling" },
• { DRM_HDMI_OUTPUT_YCBCR_LQ, "output_ycbcr_low_subsampling" },
• { DRM_HDMI_OUTPUT_INVALID, "invalid_output" },

+};

+/**

• • drm_get_hdmi_output_name - return a string for a given hdmi output enum
• • @type: enum of output type
• */

+const char *drm_get_hdmi_output_name(enum drm_hdmi_output_type type) +{

• return drm_hdmi_output_enum_list[type].name;

+} +EXPORT_SYMBOL(drm_get_hdmi_output_name);

• /**
  • drm_display_info_set_bus_formats - set the supported bus formats
  • @info: display info to store bus formats in

@@ -789,6 +814,13 @@ int drm_connector_create_standard_properties(struct drm_device *dev) return -ENOMEM; dev->mode_config.link_status_property = prop;

• prop = drm_property_create_enum(dev, 0, "hdmi_output_format",

• 			drm_hdmi_output_enum_list,
  

• 			ARRAY_SIZE(drm_hdmi_output_enum_list));
  

• if (!prop)

• return -ENOMEM;
  

• dev->mode_config.hdmi_output_property = prop;
• return 0; }

diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h index 1305fe9..5ba1f32 100644 --- a/include/drm/drm_connector.h +++ b/include/drm/drm_connector.h @@ -321,6 +321,17 @@ struct drm_tv_connector_state { unsigned int hue; };

+/* HDMI output pixel format */ +enum drm_hdmi_output_type {

• DRM_HDMI_OUTPUT_DEFAULT_RGB, /* default RGB */
• DRM_HDMI_OUTPUT_YCBCR444, /* YCBCR 444 */
• DRM_HDMI_OUTPUT_YCBCR422, /* YCBCR 422 */
• DRM_HDMI_OUTPUT_YCBCR420, /* YCBCR 420 */
• DRM_HDMI_OUTPUT_YCBCR_HQ, /* Highest subsampled YUV */
• DRM_HDMI_OUTPUT_YCBCR_LQ, /* Lowest subsampled YUV */
• DRM_HDMI_OUTPUT_INVALID, /* Guess what ? */

+};

• /**
  • struct drm_connector_state - mutable connector state
  • @connector: backpointer to the connector

@@ -365,6 +376,12 @@ struct drm_connector_state { * upscaling, mostly used for built-in panels. */ unsigned int scaling_mode;

• /**

• * @hdmi_output: Connector property to control the
  

• * HDMI output mode (RGB/YCBCR444/422/420).
  

• */
  

• enum drm_hdmi_output_type hdmi_output; };

  /**

@@ -993,6 +1010,7 @@ static inline void drm_connector_unreference(struct drm_connector *connector)

const char *drm_get_connector_status_name(enum drm_connector_status status); const char *drm_get_subpixel_order_name(enum subpixel_order order); +const char *drm_get_hdmi_output_name(enum drm_hdmi_output_type type); const char *drm_get_dpms_name(int val); const char *drm_get_dvi_i_subconnector_name(int val); const char *drm_get_dvi_i_select_name(int val); diff --git a/include/drm/drm_mode_config.h b/include/drm/drm_mode_config.h index 4298171..1887261 100644 --- a/include/drm/drm_mode_config.h +++ b/include/drm/drm_mode_config.h @@ -740,6 +740,11 @@ struct drm_mode_config { * the position of the output on the host's screen. */ struct drm_property *suggested_y_property;

• /**

• * @hdmi_output_property: output pixel format from HDMI display
  

• * Default is set for RGB
  

• */
  

• struct drm_property *hdmi_output_property;

  /* dumb ioctl parameters */ uint32_t preferred_depth, prefer_shadow;

-- 2.7.4