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

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

On Thu, Oct 03, 2019 at 01:46:16PM +0530, Sharma, Shashank wrote:
> 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 ?

The spec version is not particularly interesting. New specs just add more
modes. If we really want to indicate that somehow I think a few comments
would do.

> > 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 ?

See the next patch.

> > +}
> > +
> >   /*
> >    * 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

-- 
Ville Syrjälä
Intel
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