[PATCH 3/3] drm/debugfs: add an "edid_override" file per connector

[Thomas Wood]

Add a file to debugfs for each connector that allows the edid data to be
overridden.

Signed-off-by: Thomas Wood <thomas.wood at intel.com>
---
 drivers/gpu/drm/drm_crtc.c         |  4 +++
 drivers/gpu/drm/drm_debugfs.c      | 56 ++++++++++++++++++++++++++++++++++++++
 drivers/gpu/drm/drm_probe_helper.c |  9 +++++-
 include/drm/drm_crtc.h             |  1 +
 4 files changed, 69 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 59a2784..8543eac 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3701,6 +3701,10 @@ int drm_mode_connector_update_edid_property(struct drm_connector *connector,
 	struct drm_device *dev = connector->dev;
 	int ret, size;
 
+	/* ignore requests to set edid when overridden */
+	if (connector->override_edid)
+		return 0;
+
 	if (connector->edid_blob_ptr)
 		drm_property_destroy_blob(dev, connector->edid_blob_ptr);
 
diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index b57b614..2c666ba 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/export.h>
 #include <drm/drmP.h>
+#include <drm/drm_edid.h>
 
 #if defined(CONFIG_DEBUG_FS)
 
@@ -295,6 +296,55 @@ static ssize_t connector_write(struct file *file, const char __user *ubuf,
 	return len;
 }
 
+static int edid_show(struct seq_file *m, void *data)
+{
+	struct drm_connector *connector = m->private;
+	struct drm_property_blob *edid = connector->edid_blob_ptr;
+
+	if (connector->override_edid && edid)
+		seq_write(m, edid->data, edid->length);
+
+	return 0;
+}
+
+static int edid_open(struct inode *inode, struct file *file)
+{
+	struct drm_connector *dev = inode->i_private;
+
+	return single_open(file, edid_show, dev);
+}
+
+static ssize_t edid_write(struct file *file, const char __user *ubuf,
+			  size_t len, loff_t *offp)
+{
+	struct seq_file *m = file->private_data;
+	struct drm_connector *connector = m->private;
+
+	if (len >= EDID_LENGTH) {
+		drm_mode_connector_update_edid_property(connector,
+							(struct edid *) ubuf);
+		connector->override_edid = true;
+	} else {
+		if (connector->override_edid) {
+			connector->override_edid = false;
+			drm_mode_connector_update_edid_property(connector,
+								NULL);
+		}
+	}
+
+	return len;
+}
+
+static const struct file_operations drm_edid_fops = {
+	.owner = THIS_MODULE,
+	.open = edid_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+	.write = edid_write
+};
+
+
 static const struct file_operations drm_connector_fops = {
 	.owner = THIS_MODULE,
 	.open = connector_open,
@@ -325,6 +375,12 @@ int drm_debugfs_connector_add(struct drm_connector *connector)
 	if (!ent)
 		return -ENOMEM;
 
+	/* edid */
+	ent = debugfs_create_file("edid_override", S_IRUGO, root, connector,
+				  &drm_edid_fops);
+	if (!ent)
+		return -ENOMEM;
+
 	return 0;
 }
 
diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c
index 79f07f2..1f0dc77 100644
--- a/drivers/gpu/drm/drm_probe_helper.c
+++ b/drivers/gpu/drm/drm_probe_helper.c
@@ -130,7 +130,14 @@ static int drm_helper_probe_single_connector_modes_merge_bits(struct drm_connect
 	count = drm_load_edid_firmware(connector);
 	if (count == 0)
 #endif
-		count = (*connector_funcs->get_modes)(connector);
+	{
+		if (connector->override_edid) {
+			struct edid *edid = (struct edid *) connector->edid_blob_ptr->data;
+
+			count = drm_add_edid_modes(connector, edid);
+		} else
+			count = (*connector_funcs->get_modes)(connector);
+	}
 
 	if (count == 0 && connector->status == connector_status_connected)
 		count = drm_add_modes_noedid(connector, 1024, 768);
diff --git a/include/drm/drm_crtc.h b/include/drm/drm_crtc.h
index f04f4b9..11fce43 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -513,6 +513,7 @@ struct drm_connector {
 
 	/* forced on connector */
 	enum drm_connector_force force;
+	bool override_edid;
 	uint32_t encoder_ids[DRM_CONNECTOR_MAX_ENCODER];
 	struct drm_encoder *encoder; /* currently active encoder */
 
-- 
1.9.0