Re: [Intel-gfx] [PATCH v3 04/13] drm/edid: abstract debugfs override EDID set/reset

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Jun 22, 2022 at 01:59:18PM +0300, Jani Nikula wrote:
> Add functions drm_edid_override_set() and drm_edid_override_reset() to
> support "edid_override" connector debugfs, and to hide the details about
> it in drm_edid.c. No functional changes at this time.
> 
> Also note in the connector.override_edid flag kernel-doc that this is
> only supposed to be modified by the code doing debugfs EDID override
> handling. Currently, it is still being modified by amdgpu in
> create_eml_sink() and handle_edid_mgmt() for reasons unknown. This was
> added in commit 4562236b3bc0 ("drm/amd/dc: Add dc display driver (v2)")
> and later moved to amdgpu_dm.c in commit e7b07ceef2a6 ("drm/amd/display:
> Merge amdgpu_dm_types and amdgpu_dm").
> 
> Signed-off-by: Jani Nikula <jani.nikula@intel.com>

Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/drm_crtc_internal.h |  2 ++
>  drivers/gpu/drm/drm_debugfs.c       | 21 +++++----------------
>  drivers/gpu/drm/drm_edid.c          | 26 ++++++++++++++++++++++++++
>  include/drm/drm_connector.h         |  6 +++++-
>  4 files changed, 38 insertions(+), 17 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_crtc_internal.h b/drivers/gpu/drm/drm_crtc_internal.h
> index aecab5308bae..56041b604881 100644
> --- a/drivers/gpu/drm/drm_crtc_internal.h
> +++ b/drivers/gpu/drm/drm_crtc_internal.h
> @@ -286,3 +286,5 @@ int drm_mode_page_flip_ioctl(struct drm_device *dev,
>  
>  /* drm_edid.c */
>  void drm_mode_fixup_1366x768(struct drm_display_mode *mode);
> +int drm_edid_override_set(struct drm_connector *connector, const void *edid, size_t size);
> +int drm_edid_override_reset(struct drm_connector *connector);
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index fb04b7a984de..493922069c90 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -350,31 +350,20 @@ static ssize_t edid_write(struct file *file, const char __user *ubuf,
>  	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_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_connector_update_edid_property(connector, edid);
> -		if (!ret)
> -			connector->override_edid = true;
> -	}
> +	if (len == 5 && !strncmp(buf, "reset", 5))
> +		ret = drm_edid_override_reset(connector);
> +	else
> +		ret = drm_edid_override_set(connector, buf, len);
>  
>  	kfree(buf);
>  
> -	return (ret) ? ret : len;
> +	return ret ? ret : len;
>  }
>  
>  /*
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index e360e1a269f4..c3f0f0a5a8a9 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -2161,6 +2161,32 @@ static struct edid *drm_get_override_edid(struct drm_connector *connector,
>  	return IS_ERR(override) ? NULL : override;
>  }
>  
> +/* For debugfs edid_override implementation */
> +int drm_edid_override_set(struct drm_connector *connector, const void *edid,
> +			  size_t size)
> +{
> +	int ret;
> +
> +	if (size < EDID_LENGTH || edid_size(edid) > size)
> +		return -EINVAL;
> +
> +	connector->override_edid = false;
> +
> +	ret = drm_connector_update_edid_property(connector, edid);
> +	if (!ret)
> +		connector->override_edid = true;
> +
> +	return ret;
> +}
> +
> +/* For debugfs edid_override implementation */
> +int drm_edid_override_reset(struct drm_connector *connector)
> +{
> +	connector->override_edid = false;
> +
> +	return drm_connector_update_edid_property(connector, NULL);
> +}
> +
>  /**
>   * drm_add_override_edid_modes - add modes from override/firmware EDID
>   * @connector: connector we're probing
> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index 94b422b55cc1..a1705d6b3fba 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1527,7 +1527,11 @@ struct drm_connector {
>  	struct drm_cmdline_mode cmdline_mode;
>  	/** @force: a DRM_FORCE_<foo> state for forced mode sets */
>  	enum drm_connector_force force;
> -	/** @override_edid: has the EDID been overwritten through debugfs for testing? */
> +	/**
> +	 * @override_edid: has the EDID been overwritten through debugfs for
> +	 * testing? Do not modify outside of drm_edid_override_set() and
> +	 * drm_edid_override_reset().
> +	 */
>  	bool override_edid;
>  	/** @epoch_counter: used to detect any other changes in connector, besides status */
>  	u64 epoch_counter;
> -- 
> 2.30.2

-- 
Ville Syrjälä
Intel