drm/debugfs: add an "edid_override" file per connector

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@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index c304e5650bc8e22f249cbc01600230334ec3774a..7db6251c38e7a67ab43e845b7c6746f27d6224b2 100644 (file)
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -3763,6 +3763,10 @@ 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 8ab3f3e38643ec3f2b11cdf0335cfd84d87a20fc..13bd42923dd4e2b4ca018e3ee2b1cb09a30b4677 100644 (file)
--- 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 d22676b89cbb337147ec319fe5af4963e5e9f1d8..db7d250f7ac753dd244307d49217726e101df51e 100644 (file)
--- 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 d4b0a6a4ad9bc3e40b495c061e4b3c97aae3be98..857bbb1551f80e4402f0d58050852512202cd7c5 100644 (file)
--- a/include/drm/drm_crtc.h
+++ b/include/drm/drm_crtc.h
@@ -533,6 +533,7 @@ 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 */