Add a file to debugfs for each connector to allow the EDID to be
overridden.
v2: Copy ubuf before accessing it and reject invalid length data. (David
Herrmann)
Ensure override_edid is reset when a new EDID value is written.
(David Herrmann)
Fix the debugfs file permissions. (David Herrmann)
Signed-off-by: Thomas Wood <thomas.wood at intel.com>
---
drivers/gpu/drm/drm_crtc.c | 4 +++
drivers/gpu/drm/drm_debugfs.c | 68 ++++++++++++++++++++++++++++++++++++++
drivers/gpu/drm/drm_probe_helper.c | 9 ++++-
include/drm/drm_crtc.h | 1 +
4 files changed, 81 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index fdb69f7..4b3bbc4 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3916,6 +3916,10 @@ 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 8ab3f3e..13bd429 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)
@@ -304,6 +305,67 @@ 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;
+ char *buf;
+ struct edid *edid;
+ int ret;
+
+ buf = memdup_user(ubuf, len);
+ if (IS_ERR(buf))
+ return PTR_ERR(buf);
+
+ edid = (struct edid *) buf;
+
+ if (len == 5 && !strncmp(buf, "reset", 5)) {
+ connector->override_edid = false;
+ ret = drm_mode_connector_update_edid_property(connector, NULL);
+ } else if (len < EDID_LENGTH ||
+ EDID_LENGTH * (1 + edid->extensions) > len)
+ ret = -EINVAL;
+ else {
+ connector->override_edid = false;
+ ret = drm_mode_connector_update_edid_property(connector, edid);
+ if (!ret)
+ connector->override_edid = true;
+ }
+
+ kfree(buf);
+
+ return (ret) ? ret : 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,
@@ -333,6 +395,12 @@ int drm_debugfs_connector_add(struct drm_connector
*connector)
if (!ent)
goto error;
+ /* edid */
+ ent = debugfs_create_file("edid_override", S_IRUGO | S_IWUSR, root,
+ connector, &drm_edid_fops);
+ if (!ent)
+ goto error;
+
return 0;
error:
diff --git a/drivers/gpu/drm/drm_probe_helper.c
b/drivers/gpu/drm/drm_probe_helper.c
index d22676b..db7d250 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 67a33bc..d09b471 100644
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -537,6 +537,7 @@ 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 */
--
1.9.3
