[PATCH] drm/edid: Allow comma separated edid binaries. (v2)

[Jani Nikula]

On Wed, 26 Aug 2015, Bob Paauwe <bob.j.paauwe at intel.com> wrote:
> Allow comma separated filenames in the edid_firmware parameter.
>
> For example:
>
> edid_firmware=eDP-1:edid/1280x480.bin,DP-2:edid/1920x1080.bin
>
> v2: Use strsep() to simplify parsing of comma seperated string. (Matt)
>     Move initial bail before strdup. (Matt)
>
> Reviewed-by: Matt Roper <matthew.d.roper at intel.com>
> Signed-off-by: Bob Paauwe <bob.j.paauwe at intel.com>
> ---
>  drivers/gpu/drm/drm_edid_load.c | 44 ++++++++++++++++++++++++++++++++---------
>  1 file changed, 35 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid_load.c b/drivers/gpu/drm/drm_edid_load.c
> index c5605fe..93b9275 100644
> --- a/drivers/gpu/drm/drm_edid_load.c
> +++ b/drivers/gpu/drm/drm_edid_load.c
> @@ -264,27 +264,53 @@ out:
>  int drm_load_edid_firmware(struct drm_connector *connector)
>  {
>  	const char *connector_name = connector->name;
> -	char *edidname = edid_firmware, *last, *colon;
> +	char *edidname, *last, *colon, *fwstr, *edidstr, *fallback = NULL;
>  	int ret;
>  	struct edid *edid;
>  
> -	if (*edidname == '\0')
> +	if (edid_firmware[0] == '\0')
>  		return 0;
>  
> -	colon = strchr(edidname, ':');
> -	if (colon != NULL) {
> -		if (strncmp(connector_name, edidname, colon - edidname))
> -			return 0;
> -		edidname = colon + 1;
> -		if (*edidname == '\0')
> -			return 0;
> +	/*
> +	 * If there are multiple edid files specified and separated
> +	 * by commas, search through the list looking for one that
> +	 * matches the connector.
> +	 *
> +	 * If there's one or more that don't't specify a connector, keep
> +	 * the last one found one as a fallback.
> +	 */
> +	fwstr = kstrdup(edid_firmware, GFP_KERNEL);
> +	edidstr = fwstr;
> +
> +	while ((edidname = strsep(&edidstr, ","))) {
> +		colon = strchr(edidname, ':');
> +		if (colon != NULL) {
> +			if (strncmp(connector_name, edidname, colon-edidname))
> +				continue;
> +			edidname = colon + 1;
> +			break;
> +		} else {
> +			if (*edidname != '\0') /* corner case: multiple ',' */
> +				fallback = edidname;
> +		}
> +
>  	}
>  
> +	if (fallback == NULL && edidname == NULL) {
> +		kfree(fwstr);
> +		return 0;
> +	}
> +
> +	if (edidname == NULL && fallback)
> +		edidname = fallback;
> +

I guess I might write that as either:

	if (!edidname)
        	edidname = fallback;

	if (!edidname) {
		kfree(fwstr);
                return 0;
	}

or:

	if (!edidname) {
        	if (!fallback) {
                	kfree(fwstr);
                        return 0;
                }
                edidname = fallback;
	}

to make it faster to read, but meh. Up to you.

This will need an update to Documentation/kernel-parameters.txt
though. With that updated, this is

Reviewed-by: Jani Nikula <jani.nikula at intel.com>


>  	last = edidname + strlen(edidname) - 1;
>  	if (*last == '\n')
>  		*last = '\0';
>  
>  	edid = edid_load(connector, edidname, connector_name);
> +	kfree(fwstr);
> +
>  	if (IS_ERR_OR_NULL(edid))
>  		return 0;
>  
> -- 
> 2.1.0
>
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-- 
Jani Nikula, Intel Open Source Technology Center