Re: [PATCH v3 1/4] drm/edid: Abstract away cea_edid_modes[]

["Sharma, Shashank" <shashank.sharma@intel.com>]

Hello Ville,

On 9/25/2019 7:24 PM, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>
> We're going to need two cea mode tables (on for VICs < 128,
> another one for VICs >= 193). To that end replace the direct
> edid_cea_modes[] lookups with a function call. And we'll rename
> the array to edid_cea_modes_0[] to indicathe how it's to be
Should we call it something which indicates the spec version, instead of 
a random '0', like edid_cea_861_F_modes[] and the next one as _G_modes 
or CTA_3 modes ?
> indexed.
>
> Cc: Hans Verkuil <hansverk@cisco.com>
> Cc: Shashank Sharma <shashank.sharma@intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> ---
>   drivers/gpu/drm/drm_edid.c | 80 +++++++++++++++++++++++++++-----------
>   1 file changed, 58 insertions(+), 22 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
> index 3c9703b08491..b700fc075257 100644
> --- a/drivers/gpu/drm/drm_edid.c
> +++ b/drivers/gpu/drm/drm_edid.c
> @@ -707,12 +707,11 @@ static const struct minimode extra_modes[] = {
>   };
>   
>   /*
> - * Probably taken from CEA-861 spec.
> - * This table is converted from xorg's hw/xfree86/modes/xf86EdidModes.c.
> + * From CEA/CTA-861 spec.
>    *
> - * Index using the VIC.
> + * Index with VIC.
>    */
> -static const struct drm_display_mode edid_cea_modes[] = {
> +static const struct drm_display_mode edid_cea_modes_0[] = {
>   	/* 0 - dummy, VICs start at 1 */
>   	{ },
>   	/* 1 - 640x480@60Hz 4:3 */
> @@ -3067,6 +3066,25 @@ static u8 *drm_find_cea_extension(const struct edid *edid)
>   	return cea;
>   }
>   
> +static const struct drm_display_mode *cea_mode_for_vic(u8 vic)
> +{
> +	if (!vic)
> +		return NULL;
> +	if (vic < ARRAY_SIZE(edid_cea_modes_0))
> +		return &edid_cea_modes_0[vic];
> +	return NULL;
> +}
> +
> +static u8 cea_num_vics(void)
> +{
> +	return ARRAY_SIZE(edid_cea_modes_0);
> +}
> +
> +static u8 cea_next_vic(u8 vic)
> +{
> +	return vic + 1;
Is there any specific reason for adding a new helper function, just to 
return vic + 1 ?
> +}
> +
>   /*
>    * Calculate the alternate clock for the CEA mode
>    * (60Hz vs. 59.94Hz etc.)
> @@ -3104,14 +3122,14 @@ cea_mode_alternate_timings(u8 vic, struct drm_display_mode *mode)
>   	 * get the other variants by simply increasing the
>   	 * vertical front porch length.
>   	 */
> -	BUILD_BUG_ON(edid_cea_modes[8].vtotal != 262 ||
> -		     edid_cea_modes[9].vtotal != 262 ||
> -		     edid_cea_modes[12].vtotal != 262 ||
> -		     edid_cea_modes[13].vtotal != 262 ||
> -		     edid_cea_modes[23].vtotal != 312 ||
> -		     edid_cea_modes[24].vtotal != 312 ||
> -		     edid_cea_modes[27].vtotal != 312 ||
> -		     edid_cea_modes[28].vtotal != 312);
> +	BUILD_BUG_ON(cea_mode_for_vic(8)->vtotal != 262 ||
> +		     cea_mode_for_vic(9)->vtotal != 262 ||
> +		     cea_mode_for_vic(12)->vtotal != 262 ||
> +		     cea_mode_for_vic(13)->vtotal != 262 ||
> +		     cea_mode_for_vic(23)->vtotal != 312 ||
> +		     cea_mode_for_vic(24)->vtotal != 312 ||
> +		     cea_mode_for_vic(27)->vtotal != 312 ||
> +		     cea_mode_for_vic(28)->vtotal != 312);
>   
>   	if (((vic == 8 || vic == 9 ||
>   	      vic == 12 || vic == 13) && mode->vtotal < 263) ||
> @@ -3139,10 +3157,16 @@ static u8 drm_match_cea_mode_clock_tolerance(const struct drm_display_mode *to_m
>   	if (to_match->picture_aspect_ratio)
>   		match_flags |= DRM_MODE_MATCH_ASPECT_RATIO;
>   
> -	for (vic = 1; vic < ARRAY_SIZE(edid_cea_modes); vic++) {
> -		struct drm_display_mode cea_mode = edid_cea_modes[vic];
> +	for (vic = 1; vic < cea_num_vics(); vic = cea_next_vic(vic)) {
> +		const struct drm_display_mode *mode = cea_mode_for_vic(vic);
> +		struct drm_display_mode cea_mode;
>   		unsigned int clock1, clock2;
>   
> +		if (!mode)
> +			continue;
> +
> +		cea_mode = *mode;
> +
>   		/* Check both 60Hz and 59.94Hz */
>   		clock1 = cea_mode.clock;
>   		clock2 = cea_mode_alternate_clock(&cea_mode);
> @@ -3178,10 +3202,16 @@ u8 drm_match_cea_mode(const struct drm_display_mode *to_match)
>   	if (to_match->picture_aspect_ratio)
>   		match_flags |= DRM_MODE_MATCH_ASPECT_RATIO;
>   
> -	for (vic = 1; vic < ARRAY_SIZE(edid_cea_modes); vic++) {
> -		struct drm_display_mode cea_mode = edid_cea_modes[vic];
> +	for (vic = 1; vic < cea_num_vics(); vic = cea_next_vic(vic)) {
Again, why not just vic+=1 :) ?
> +		const struct drm_display_mode *mode = cea_mode_for_vic(vic);
> +		struct drm_display_mode cea_mode;
>   		unsigned int clock1, clock2;
>   
> +		if (!mode)
> +			continue;
> +
> +		cea_mode = *mode;
> +
>   		/* Check both 60Hz and 59.94Hz */
>   		clock1 = cea_mode.clock;
>   		clock2 = cea_mode_alternate_clock(&cea_mode);
> @@ -3202,7 +3232,7 @@ EXPORT_SYMBOL(drm_match_cea_mode);
>   
>   static bool drm_valid_cea_vic(u8 vic)
>   {
> -	return vic > 0 && vic < ARRAY_SIZE(edid_cea_modes);
> +	return cea_mode_for_vic(vic) != NULL;
>   }
>   
>   /**
> @@ -3214,7 +3244,13 @@ static bool drm_valid_cea_vic(u8 vic)
>    */
>   enum hdmi_picture_aspect drm_get_cea_aspect_ratio(const u8 video_code)
>   {
> -	return edid_cea_modes[video_code].picture_aspect_ratio;
> +	const struct drm_display_mode *mode;
> +
> +	mode = cea_mode_for_vic(video_code);
> +	if (mode)
> +		return mode->picture_aspect_ratio;
> +
> +	return HDMI_PICTURE_ASPECT_NONE;
>   }
>   EXPORT_SYMBOL(drm_get_cea_aspect_ratio);
>   
> @@ -3323,7 +3359,7 @@ add_alternate_cea_modes(struct drm_connector *connector, struct edid *edid)
>   		unsigned int clock1, clock2;
>   
>   		if (drm_valid_cea_vic(vic)) {
> -			cea_mode = &edid_cea_modes[vic];
> +			cea_mode = cea_mode_for_vic(vic);
>   			clock2 = cea_mode_alternate_clock(cea_mode);
>   		} else {
>   			vic = drm_match_hdmi_mode(mode);
> @@ -3398,7 +3434,7 @@ drm_display_mode_from_vic_index(struct drm_connector *connector,
>   	if (!drm_valid_cea_vic(vic))
>   		return NULL;
>   
> -	newmode = drm_mode_duplicate(dev, &edid_cea_modes[vic]);
> +	newmode = drm_mode_duplicate(dev, cea_mode_for_vic(vic));
>   	if (!newmode)
>   		return NULL;
>   
> @@ -3432,7 +3468,7 @@ static int do_y420vdb_modes(struct drm_connector *connector,
>   		if (!drm_valid_cea_vic(vic))
>   			continue;
>   
> -		newmode = drm_mode_duplicate(dev, &edid_cea_modes[vic]);
> +		newmode = drm_mode_duplicate(dev, cea_mode_for_vic(vic));
>   		if (!newmode)
>   			break;
>   		bitmap_set(hdmi->y420_vdb_modes, vic, 1);
> @@ -4001,7 +4037,7 @@ static void fixup_detailed_cea_mode_clock(struct drm_display_mode *mode)
>   	vic = drm_match_cea_mode_clock_tolerance(mode, 5);
>   	if (drm_valid_cea_vic(vic)) {
>   		type = "CEA";
> -		cea_mode = &edid_cea_modes[vic];
> +		cea_mode = cea_mode_for_vic(vic);
>   		clock1 = cea_mode->clock;
>   		clock2 = cea_mode_alternate_clock(cea_mode);
>   	} else {
- Shashank
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