linux-kernel - [PATCH v2 1/8] drm: Add crtc/encoder/bridge->mode

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Date:   Tue,  9 May 2017 18:00:08 +0100
From:   Jose Abreu <Jose.Abreu@...opsys.com>
To:     dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org
Cc:     Jose Abreu <Jose.Abreu@...opsys.com>,
        Carlos Palminha <CARLOS.PALMINHA@...opsys.com>,
        Alexey Brodkin <Alexey.Brodkin@...opsys.com>,
        Ville Syrjälä 
        <ville.syrjala@...ux.intel.com>,
        Daniel Vetter <daniel.vetter@...ll.ch>,
        Dave Airlie <airlied@...ux.ie>,
        Andrzej Hajda <a.hajda@...sung.com>,
        Archit Taneja <architt@...eaurora.org>
Subject: [PATCH v2 1/8] drm: Add crtc/encoder/bridge->mode_valid() callbacks

This adds a new callback to crtc, encoder and bridge helper functions
called mode_valid(). This callback shall be implemented if the
corresponding component has some sort of restriction in the modes
that can be displayed. A NULL callback implicates that the component
can display all the modes.

We also change the description of connector->mode_valid() callback
so that it matches the existing behaviour: It is never called in
atomic check phase.

Only the callbacks were implemented to simplify review process,
following patches will make use of them.

Signed-off-by: Jose Abreu <joabreu@...opsys.com>
Cc: Carlos Palminha <palminha@...opsys.com>
Cc: Alexey Brodkin <abrodkin@...opsys.com>
Cc: Ville Syrjälä <ville.syrjala@...ux.intel.com>
Cc: Daniel Vetter <daniel.vetter@...ll.ch>
Cc: Dave Airlie <airlied@...ux.ie>
Cc: Andrzej Hajda <a.hajda@...sung.com>
Cc: Archit Taneja <architt@...eaurora.org>
---

Changes v1->v2:
	- Change description of connector->mode_valid() (Daniel)

 include/drm/drm_bridge.h                 | 20 ++++++++++++++
 include/drm/drm_modeset_helper_vtables.h | 45 ++++++++++++++++++++++++++++++++
 2 files changed, 65 insertions(+)

diff --git a/include/drm/drm_bridge.h b/include/drm/drm_bridge.h
index fdd82fc..00c6c36 100644
--- a/include/drm/drm_bridge.h
+++ b/include/drm/drm_bridge.h
@@ -59,6 +59,26 @@ struct drm_bridge_funcs {
 	void (*detach)(struct drm_bridge *bridge);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * bridge. This should be implemented if the bridge has some sort of
+	 * restriction in the modes it can display. For example, a given bridge
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_bridge *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The paramater
diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h
index c01c328..eec2c70 100644
--- a/include/drm/drm_modeset_helper_vtables.h
+++ b/include/drm/drm_modeset_helper_vtables.h
@@ -106,6 +106,26 @@ struct drm_crtc_helper_funcs {
 	void (*commit)(struct drm_crtc *crtc);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * crtc. This should be implemented if the crtc has some sort of
+	 * restriction in the modes it can display. For example, a given crtc
+	 * may be responsible to set a clock value. If the clock can not
+	 * produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_crtc *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate a mode. The parameter mode is the
@@ -457,6 +477,26 @@ struct drm_encoder_helper_funcs {
 	void (*dpms)(struct drm_encoder *encoder, int mode);
 
 	/**
+	 * @mode_valid:
+	 *
+	 * This callback is used to check if a specific mode is valid in this
+	 * encoder. This should be implemented if the encoder has some sort
+	 * of restriction in the modes it can display. For example, a given
+	 * encoder may be responsible to set a clock value. If the clock can
+	 * not produce all the values for the available modes then this callback
+	 * can be used to restrict the number of modes to only the ones that
+	 * can be displayed.
+	 *
+	 * This is called at mode probe and at atomic check phase.
+	 *
+	 * RETURNS:
+	 *
+	 * drm_mode_status Enum
+	 */
+	enum drm_mode_status (*mode_valid)(struct drm_encoder *crtc,
+					   const struct drm_display_mode *mode);
+
+	/**
 	 * @mode_fixup:
 	 *
 	 * This callback is used to validate and adjust a mode. The parameter
@@ -795,6 +835,11 @@ struct drm_connector_helper_funcs {
 	 * (which is usually derived from the EDID data block from the sink).
 	 * See e.g. drm_helper_probe_single_connector_modes().
 	 *
+	 * This callback is never called in atomic check phase so that userspace
+	 * can override kernel sink checks in case of broken EDID with wrong
+	 * limits from the sink. You can use the remaining mode_valid()
+	 * callbacks to validate the mode against your video path.
+	 *
 	 * NOTE:
 	 *
 	 * This only filters the mode list supplied to userspace in the
-- 
1.9.1