Commit 1c26b8e0 authored by Lyude Paul's avatar Lyude Paul
Browse files

drm/probe_helper: Add drm_connector_helper_funcs.mode_valid_ctx 



This is just an atomic version of mode_valid, which is intended to be
used for situations where a driver might need to check the atomic state
of objects other than the connector itself. One such example is with
MST, where the maximum possible bandwidth on a connector can change
dynamically irregardless of the display configuration.

Changes since v1:
* Use new drm logging functions
* Make some corrections in the mode_valid_ctx kdoc
* Return error codes or 0 from ->mode_valid_ctx() on fail, and store the
  drm_mode_status in an additional function parameter
Changes since v2:
* Don't accidentally assign ret to mode->status on success, or we'll
  squash legitimate mode validation results
* Don't forget to assign MODE_OK to status in drm_connector_mode_valid()
  if we have no callbacks
* Drop leftover hunk in drm_modes.h around enum drm_mode_status
Changes since v3:
* s/return ret/return 0/ in drm_mode_validate_pipeline()
* Minor cleanup in drm_connector_mode_valid()

Tested-by: default avatarImre Deak <imre.deak@intel.com>
Reviewed-by: default avatarImre Deak <imre.deak@intel.com>
Cc: Lee Shawn C <shawn.c.lee@intel.com>
Signed-off-by: default avatarLyude Paul <lyude@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200713170746.254388-2-lyude@redhat.com
parent 1d9221e9

drivers/gpu/drm/drm_crtc_helper_internal.h

+5 −2
Original line number Diff line number Diff line
@@ -73,8 +73,11 @@ enum drm_mode_status drm_crtc_mode_valid(struct drm_crtc *crtc, 
					 const struct drm_display_mode *mode);

enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder,

					    const struct drm_display_mode *mode);

enum drm_mode_status drm_connector_mode_valid(struct drm_connector *connector,

					      struct drm_display_mode *mode);

int

drm_connector_mode_valid(struct drm_connector *connector,

			 struct drm_display_mode *mode,

			 struct drm_modeset_acquire_ctx *ctx,

			 enum drm_mode_status *status);



struct drm_encoder *

drm_connector_get_single_encoder(struct drm_connector *connector);

drivers/gpu/drm/drm_probe_helper.c

+64 −33
Original line number Diff line number Diff line
@@ -86,17 +86,19 @@ drm_mode_validate_flag(const struct drm_display_mode *mode, 
	return MODE_OK;

}



static enum drm_mode_status

static int

drm_mode_validate_pipeline(struct drm_display_mode *mode,

			    struct drm_connector *connector)

			   struct drm_connector *connector,

			   struct drm_modeset_acquire_ctx *ctx,

			   enum drm_mode_status *status)

{

	struct drm_device *dev = connector->dev;

	enum drm_mode_status ret = MODE_OK;

	struct drm_encoder *encoder;

	int ret;



	/* Step 1: Validate against connector */

	ret = drm_connector_mode_valid(connector, mode);

	if (ret != MODE_OK)

	ret = drm_connector_mode_valid(connector, mode, ctx, status);

	if (ret || *status != MODE_OK)

		return ret;



	/* Step 2: Validate against encoders and crtcs */
@@ -104,8 +106,8 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode, 
		struct drm_bridge *bridge;

		struct drm_crtc *crtc;



		ret = drm_encoder_mode_valid(encoder, mode);

		if (ret != MODE_OK) {

		*status = drm_encoder_mode_valid(encoder, mode);

		if (*status != MODE_OK) {

			/* No point in continuing for crtc check as this encoder

			 * will not accept the mode anyway. If all encoders

			 * reject the mode then, at exit, ret will not be
@@ -114,8 +116,8 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode, 
		}



		bridge = drm_bridge_chain_get_first_bridge(encoder);

		ret = drm_bridge_chain_mode_valid(bridge, mode);

		if (ret != MODE_OK) {

		*status = drm_bridge_chain_mode_valid(bridge, mode);

		if (*status != MODE_OK) {

			/* There is also no point in continuing for crtc check

			 * here. */

			continue;
@@ -125,17 +127,17 @@ drm_mode_validate_pipeline(struct drm_display_mode *mode, 
			if (!drm_encoder_crtc_ok(encoder, crtc))

				continue;



			ret = drm_crtc_mode_valid(crtc, mode);

			if (ret == MODE_OK) {

			*status = drm_crtc_mode_valid(crtc, mode);

			if (*status == MODE_OK) {

				/* If we get to this point there is at least

				 * one combination of encoder+crtc that works

				 * for this mode. Lets return now. */

				return ret;

				return 0;

			}

		}

	}



	return ret;

	return 0;

}



static int drm_helper_probe_add_cmdline_mode(struct drm_connector *connector)
@@ -196,16 +198,27 @@ enum drm_mode_status drm_encoder_mode_valid(struct drm_encoder *encoder, 
	return encoder_funcs->mode_valid(encoder, mode);

}



enum drm_mode_status drm_connector_mode_valid(struct drm_connector *connector,

					      struct drm_display_mode *mode)

int

drm_connector_mode_valid(struct drm_connector *connector,

			 struct drm_display_mode *mode,

			 struct drm_modeset_acquire_ctx *ctx,

			 enum drm_mode_status *status)

{

	const struct drm_connector_helper_funcs *connector_funcs =

		connector->helper_private;

	int ret = 0;



	if (!connector_funcs)

		*status = MODE_OK;

	else if (connector_funcs->mode_valid_ctx)

		ret = connector_funcs->mode_valid_ctx(connector, mode, ctx,

						      status);

	else if (connector_funcs->mode_valid)

		*status = connector_funcs->mode_valid(connector, mode);

	else

		*status = MODE_OK;



	if (!connector_funcs || !connector_funcs->mode_valid)

		return MODE_OK;



	return connector_funcs->mode_valid(connector, mode);

	return ret;

}



#define DRM_OUTPUT_POLL_PERIOD (10*HZ)
@@ -375,8 +388,9 @@ EXPORT_SYMBOL(drm_helper_probe_detect); 
 *      (if specified)

 *    - drm_mode_validate_flag() checks the modes against basic connector

 *      capabilities (interlace_allowed,doublescan_allowed,stereo_allowed)

 *    - the optional &drm_connector_helper_funcs.mode_valid helper can perform

 *      driver and/or sink specific checks

 *    - the optional &drm_connector_helper_funcs.mode_valid or

 *      &drm_connector_helper_funcs.mode_valid_ctx helpers can perform driver

 *      and/or sink specific checks

 *    - the optional &drm_crtc_helper_funcs.mode_valid,

 *      &drm_bridge_funcs.mode_valid and &drm_encoder_helper_funcs.mode_valid

 *      helpers can perform driver and/or source specific checks which are also
@@ -507,22 +521,39 @@ retry: 
		mode_flags |= DRM_MODE_FLAG_3D_MASK;



	list_for_each_entry(mode, &connector->modes, head) {

		if (mode->status == MODE_OK)

		if (mode->status != MODE_OK)

			continue;



		mode->status = drm_mode_validate_driver(dev, mode);

		if (mode->status != MODE_OK)

			continue;



		if (mode->status == MODE_OK)

		mode->status = drm_mode_validate_size(mode, maxX, maxY);

		if (mode->status != MODE_OK)

			continue;



		if (mode->status == MODE_OK)

		mode->status = drm_mode_validate_flag(mode, mode_flags);

		if (mode->status != MODE_OK)

			continue;



		ret = drm_mode_validate_pipeline(mode, connector, &ctx,

						 &mode->status);

		if (ret) {

			drm_dbg_kms(dev,

				    "drm_mode_validate_pipeline failed: %d\n",

				    ret);



		if (mode->status == MODE_OK)

			mode->status = drm_mode_validate_pipeline(mode,

								  connector);

			if (drm_WARN_ON_ONCE(dev, ret != -EDEADLK)) {

				mode->status = MODE_ERROR;

			} else {

				drm_modeset_backoff(&ctx);

				goto retry;

			}

		}



		if (mode->status == MODE_OK)

			mode->status = drm_mode_validate_ycbcr420(mode,

								  connector);

		if (mode->status != MODE_OK)

			continue;

		mode->status = drm_mode_validate_ycbcr420(mode, connector);

	}



prune:

include/drm/drm_modeset_helper_vtables.h

+42 −0
Original line number Diff line number Diff line
@@ -968,6 +968,48 @@ struct drm_connector_helper_funcs { 
	 */

	enum drm_mode_status (*mode_valid)(struct drm_connector *connector,

					   struct drm_display_mode *mode);



	/**

	 * @mode_valid_ctx:

	 *

	 * Callback to validate a mode for a connector, irrespective of the

	 * specific display configuration.

	 *

	 * This callback is used by the probe helpers to filter the mode list

	 * (which is usually derived from the EDID data block from the sink).

	 * See e.g. drm_helper_probe_single_connector_modes().

	 *

	 * This function is optional, and is the atomic version of

	 * &drm_connector_helper_funcs.mode_valid.

	 *

	 * To allow for accessing the atomic state of modesetting objects, the

	 * helper libraries always call this with ctx set to a valid context,

	 * and &drm_mode_config.connection_mutex will always be locked with

	 * the ctx parameter set to @ctx. This allows for taking additional

	 * locks as required.

	 *

	 * Even though additional locks may be acquired, this callback is

	 * still expected not to take any constraints into account which would

	 * be influenced by the currently set display state - such constraints

	 * should be handled in the driver's atomic check. For example, if a

	 * connector shares display bandwidth with other connectors then it

	 * would be ok to validate the minimum bandwidth requirement of a mode

	 * against the maximum possible bandwidth of the connector. But it

	 * wouldn't be ok to take the current bandwidth usage of other

	 * connectors into account, as this would change depending on the

	 * display state.

	 *

	 * Returns:

	 * 0 if &drm_connector_helper_funcs.mode_valid_ctx succeeded and wrote

	 * the &enum drm_mode_status value to @status, or a negative error

	 * code otherwise.

	 *

	 */

	int (*mode_valid_ctx)(struct drm_connector *connector,

			      struct drm_display_mode *mode,

			      struct drm_modeset_acquire_ctx *ctx,

			      enum drm_mode_status *status);



	/**

	 * @best_encoder:

	 *

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