[PATCH v2 4/4] drm: handle override edid and firmware EDID at drm_do_get_edid() level

[Jani Nikula]

Handle debugfs override edid and firmware edid at the low level to
transparently and completely replace the real edid. Previously, we
practically only used the modes from the override EDID, and none of the
other data. This also prevents actual EDID reads when the EDID is to be
overridden, but retains the DDC probe.

Move firmware EDID loading from helper to core, as the functionality
moves to lower level as well. This will result in a change of module
parameter from drm_kms_helper.edid_firmware to drm.edid_firmware, which
arguably makes more sense anyway.

FIXME: validate override edid, deduplicate firmware edid validation.

v2: move firmware loading to core

Signed-off-by: Jani Nikula <jani.nikula at intel.com>
---
 drivers/gpu/drm/Kconfig            |  2 +-
 drivers/gpu/drm/Makefile           |  2 +-
 drivers/gpu/drm/drm_edid.c         | 15 +++++++++++++++
 drivers/gpu/drm/drm_probe_helper.c | 19 +------------------
 4 files changed, 18 insertions(+), 20 deletions(-)

diff --git a/drivers/gpu/drm/Kconfig b/drivers/gpu/drm/Kconfig
index 90bc65d07a35..f983ef60299c 100644
--- a/drivers/gpu/drm/Kconfig
+++ b/drivers/gpu/drm/Kconfig
@@ -101,7 +101,7 @@ config DRM_FBDEV_EMULATION
 
 config DRM_LOAD_EDID_FIRMWARE
 	bool "Allow to specify an EDID data set instead of probing for it"
-	depends on DRM_KMS_HELPER
+	depends on DRM
 	help
 	  Say Y here, if you want to use EDID data to be loaded from the
 	  /lib/firmware directory or one of the provided built-in
diff --git a/drivers/gpu/drm/Makefile b/drivers/gpu/drm/Makefile
index 92de3991fa56..a10ac095608f 100644
--- a/drivers/gpu/drm/Makefile
+++ b/drivers/gpu/drm/Makefile
@@ -27,13 +27,13 @@ drm-$(CONFIG_DRM_PANEL) += drm_panel.o
 drm-$(CONFIG_OF) += drm_of.o
 drm-$(CONFIG_AGP) += drm_agpsupport.o
 drm-$(CONFIG_DEBUG_FS) += drm_debugfs.o drm_debugfs_crc.o
+drm-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
 
 drm_kms_helper-y := drm_crtc_helper.o drm_dp_helper.o drm_probe_helper.o \
 		drm_plane_helper.o drm_dp_mst_topology.o drm_atomic_helper.o \
 		drm_kms_helper_common.o drm_dp_dual_mode_helper.o \
 		drm_simple_kms_helper.o drm_modeset_helper.o
 
-drm_kms_helper-$(CONFIG_DRM_LOAD_EDID_FIRMWARE) += drm_edid_load.o
 drm_kms_helper-$(CONFIG_DRM_FBDEV_EMULATION) += drm_fb_helper.o
 drm_kms_helper-$(CONFIG_DRM_KMS_CMA_HELPER) += drm_fb_cma_helper.o
 drm_kms_helper-$(CONFIG_DRM_DP_AUX_CHARDEV) += drm_dp_aux_dev.o
diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
index e1743ab276dc..4007998d5ce3 100644
--- a/drivers/gpu/drm/drm_edid.c
+++ b/drivers/gpu/drm/drm_edid.c
@@ -1309,6 +1309,10 @@ static void connector_bad_edid(struct drm_connector *connector,
  * level, drivers must make all reasonable efforts to expose it as an I2C
  * adapter and use drm_get_edid() instead of abusing this function.
  *
+ * The EDID may be overridden using debugfs override_edid or firmare EDID
+ * (drm_load_edid_firmware()), in this priority order. Having either of them
+ * bypasses actual EDID reads.
+ *
  * Return: Pointer to valid EDID or NULL if we couldn't find any.
  */
 struct edid *drm_do_get_edid(struct drm_connector *connector,
@@ -1318,6 +1322,17 @@ struct edid *drm_do_get_edid(struct drm_connector *connector,
 {
 	int i, j = 0, valid_extensions = 0;
 	u8 *edid, *new;
+	struct edid *override = NULL;
+
+	if (connector->override_edid)
+		override = drm_edid_duplicate((const struct edid *)
+					      connector->edid_blob_ptr->data);
+
+	if (!override)
+		override = drm_load_edid_firmware(connector);
+
+	if (!IS_ERR_OR_NULL(override))
+		return override;
 
 	if ((edid = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
 		return NULL;
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 358957118ca9..871326cbc465 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -199,8 +199,6 @@ drm_connector_detect(struct drm_connector *connector, bool force)
  *    drm_mode_probed_add(). New modes start their life with status as OK.
  *    Modes are added from a single source using the following priority order.
  *
- *    - debugfs 'override_edid' (used for testing only)
- *    - firmware EDID (drm_load_edid_firmware())
  *    - &drm_connector_helper_funcs.get_modes vfunc
  *    - if the connector status is connector_status_connected, standard
  *      VESA DMT modes up to 1024x768 are automatically added
@@ -305,22 +303,7 @@ int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
 		goto prune;
 	}
 
-	if (connector->override_edid) {
-		struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
-
-		count = drm_add_edid_modes(connector, edid);
-		drm_edid_to_eld(connector, edid);
-	} else {
-		struct edid *edid = drm_load_edid_firmware(connector);
-		if (!IS_ERR_OR_NULL(edid)) {
-			drm_mode_connector_update_edid_property(connector, edid);
-			count = drm_add_edid_modes(connector, edid);
-			drm_edid_to_eld(connector, edid);
-			kfree(edid);
-		}
-		if (count == 0)
-			count = (*connector_funcs->get_modes)(connector);
-	}
+	count = (*connector_funcs->get_modes)(connector);
 
 	if (count == 0 && connector->status == connector_status_connected)
 		count = drm_add_modes_noedid(connector, 1024, 768);
-- 
2.1.4