Re: [Intel-gfx] [PATCH v2 3/6] drm/edid: abstract OUI conversion to 24-bit int

["Shankar, Uma" <uma.shankar@intel.com>]

> -----Original Message-----
> From: dri-devel <dri-devel-bounces@lists.freedesktop.org> On Behalf Of Jani Nikula
> Sent: Tuesday, August 31, 2021 7:48 PM
> To: intel-gfx@lists.freedesktop.org
> Cc: dri-devel@lists.freedesktop.org; ville.syrjala@linux.intel.com; Nikula, Jani
> <jani.nikula@intel.com>
> Subject: [PATCH v2 3/6] drm/edid: abstract OUI conversion to 24-bit int
> 
> Replace the open coded OUI conversion from three bytes to a 24-bit int, as we'll be
> adding one more user shortly. No functional changes.
> 
> Side note: CTA-861 format has the OUI bytes in reverse order.

Looks ok to me.
Reviewed-by: Uma Shankar <uma.shankar@intel.com>

> Signed-off-by: Jani Nikula <jani.nikula@intel.com>
> ---
>  drivers/gpu/drm/drm_edid.c | 17 +++++++----------
>  1 file changed, 7 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index
> 6325877c5fd6..92974b1478bc 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -49,6 +49,11 @@
>  	(((edid)->version > (maj)) || \
>  	 ((edid)->version == (maj) && (edid)->revision > (min)))
> 
> +static int oui(u8 first, u8 second, u8 third) {
> +	return (first << 16) | (second << 8) | third; }
> +
>  #define EDID_EST_TIMINGS 16
>  #define EDID_STD_TIMINGS 8
>  #define EDID_DETAILED_TIMINGS 4
> @@ -4113,32 +4118,24 @@ cea_db_offsets(const u8 *cea, int *start, int *end)
> 
>  static bool cea_db_is_hdmi_vsdb(const u8 *db)  {
> -	int hdmi_id;
> -
>  	if (cea_db_tag(db) != VENDOR_BLOCK)
>  		return false;
> 
>  	if (cea_db_payload_len(db) < 5)
>  		return false;
> 
> -	hdmi_id = db[1] | (db[2] << 8) | (db[3] << 16);
> -
> -	return hdmi_id == HDMI_IEEE_OUI;
> +	return oui(db[3], db[2], db[1]) == HDMI_IEEE_OUI;
>  }
> 
>  static bool cea_db_is_hdmi_forum_vsdb(const u8 *db)  {
> -	unsigned int oui;
> -
>  	if (cea_db_tag(db) != VENDOR_BLOCK)
>  		return false;
> 
>  	if (cea_db_payload_len(db) < 7)
>  		return false;
> 
> -	oui = db[3] << 16 | db[2] << 8 | db[1];
> -
> -	return oui == HDMI_FORUM_IEEE_OUI;
> +	return oui(db[3], db[2], db[1]) == HDMI_FORUM_IEEE_OUI;
>  }
> 
>  static bool cea_db_is_vcdb(const u8 *db)
> --
> 2.30.2