On Wed, Jun 18, 2014 at 12:52 PM, Thomas Wood <thomas.wood@xxxxxxxxx> wrote:
> 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@xxxxxxxxx>
One minor nit below, but either way:
Reviewed-by: Alex Deucher <alexander.deucher@xxxxxxx>
> ---
> 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;
Might be worth doing some minimal validation of the EDID (e.g., make
sure it has a valid header).
Alex
> + 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
>
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