Re: [PATCH v1 04/35] drm/modes: Introduce 480i and 576i modes

[Thomas Zimmermann <tzimmermann@xxxxxxx>]

Hi

Am 02.08.22 um 15:58 schrieb Jani Nikula:
> On Fri, 29 Jul 2022, Maxime Ripard <maxime@xxxxxxxxxx> wrote:
> > Multiple drivers (meson, vc4) define the analog TV 525-lines and 625-lines
> > modes in the drivers.
> >
> > Since those modes are fairly standards, and that we'll need to use them in
> > more places in the future, let's move the meson definition into the
> > framework.
>
> I think you should always expose interfaces, not data. Data is not an
> interface, and I think this sets a bad example that will be cargo
> culted.

Although I wrote the opposite wrt patch 8, I agree with Jani here when 
it comes to 'official' interfaces. The cases I've seen of exported data 
structures often lead to intransparent code.

Best regards
Thomas

> BR,
> Jani.
>
> > The meson one was chosen because vc4's isn't accurate and doesn't amount to
> > 525 and 625 lines.
> >
> > Signed-off-by: Maxime Ripard <maxime@xxxxxxxxxx>
> >
> > diff --git a/drivers/gpu/drm/drm_modes.c b/drivers/gpu/drm/drm_modes.c
> > index 304004fb80aa..a4c1bd688338 100644
> > --- a/drivers/gpu/drm/drm_modes.c
> > +++ b/drivers/gpu/drm/drm_modes.c
> > @@ -48,6 +48,24 @@
> >   
> >   #include "drm_crtc_internal.h"
> >   
> > +const struct drm_display_mode drm_mode_480i = {
> > +	DRM_MODE("720x480i", DRM_MODE_TYPE_DRIVER, 13500,
> > +		 720, 739, 801, 858, 0,
> > +		 480, 488, 494, 525, 0,
> > +		 DRM_MODE_FLAG_INTERLACE),
> > +	.picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3,
> > +};
> > +EXPORT_SYMBOL_GPL(drm_mode_480i);
> > +
> > +const struct drm_display_mode drm_mode_576i = {
> > +	DRM_MODE("720x576i", DRM_MODE_TYPE_DRIVER, 13500,
> > +		 720, 732, 795, 864, 0,
> > +		 576, 580, 586, 625, 0,
> > +		 DRM_MODE_FLAG_INTERLACE),
> > +	.picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3,
> > +};
> > +EXPORT_SYMBOL_GPL(drm_mode_576i);
> > +
> >   /**
> >    * drm_mode_debug_printmodeline - print a mode to dmesg
> >    * @mode: mode to print
> > diff --git a/drivers/gpu/drm/meson/meson_encoder_cvbs.c b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > index 8110a6e39320..98ec3e563155 100644
> > --- a/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > +++ b/drivers/gpu/drm/meson/meson_encoder_cvbs.c
> > @@ -45,21 +45,11 @@ struct meson_encoder_cvbs {
> >   struct meson_cvbs_mode meson_cvbs_modes[MESON_CVBS_MODES_COUNT] = {
> >   	{ /* PAL */
> >   		.enci = &meson_cvbs_enci_pal,
> > -		.mode = {
> > -			DRM_MODE("720x576i", DRM_MODE_TYPE_DRIVER, 13500,
> > -				 720, 732, 795, 864, 0, 576, 580, 586, 625, 0,
> > -				 DRM_MODE_FLAG_INTERLACE),
> > -			.picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3,
> > -		},
> > +		.mode = &drm_mode_576i,
> >   	},
> >   	{ /* NTSC */
> >   		.enci = &meson_cvbs_enci_ntsc,
> > -		.mode = {
> > -			DRM_MODE("720x480i", DRM_MODE_TYPE_DRIVER, 13500,
> > -				720, 739, 801, 858, 0, 480, 488, 494, 525, 0,
> > -				DRM_MODE_FLAG_INTERLACE),
> > -			.picture_aspect_ratio = HDMI_PICTURE_ASPECT_4_3,
> > -		},
> > +		.mode = &drm_mode_480i,
> >   	},
> >   };
> >   
> > @@ -71,7 +61,7 @@ meson_cvbs_get_mode(const struct drm_display_mode *req_mode)
> >   	for (i = 0; i < MESON_CVBS_MODES_COUNT; ++i) {
> >   		struct meson_cvbs_mode *meson_mode = &meson_cvbs_modes[i];
> >   
> > -		if (drm_mode_match(req_mode, &meson_mode->mode,
> > +		if (drm_mode_match(req_mode, meson_mode->mode,
> >   				   DRM_MODE_MATCH_TIMINGS |
> >   				   DRM_MODE_MATCH_CLOCK |
> >   				   DRM_MODE_MATCH_FLAGS |
> > @@ -104,7 +94,7 @@ static int meson_encoder_cvbs_get_modes(struct drm_bridge *bridge,
> >   	for (i = 0; i < MESON_CVBS_MODES_COUNT; ++i) {
> >   		struct meson_cvbs_mode *meson_mode = &meson_cvbs_modes[i];
> >   
> > -		mode = drm_mode_duplicate(priv->drm, &meson_mode->mode);
> > +		mode = drm_mode_duplicate(priv->drm, meson_mode->mode);
> >   		if (!mode) {
> >   			dev_err(priv->dev, "Failed to create a new display mode\n");
> >   			return 0;
> > diff --git a/drivers/gpu/drm/meson/meson_encoder_cvbs.h b/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> > index 61d9d183ce7f..26cefb202924 100644
> > --- a/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> > +++ b/drivers/gpu/drm/meson/meson_encoder_cvbs.h
> > @@ -16,7 +16,7 @@
> >   
> >   struct meson_cvbs_mode {
> >   	struct meson_cvbs_enci_mode *enci;
> > -	struct drm_display_mode mode;
> > +	const struct drm_display_mode *mode;
> >   };
> >   
> >   #define MESON_CVBS_MODES_COUNT	2
> > diff --git a/include/drm/drm_modes.h b/include/drm/drm_modes.h
> > index a80ae9639e96..b4a440e2688c 100644
> > --- a/include/drm/drm_modes.h
> > +++ b/include/drm/drm_modes.h
> > @@ -394,6 +394,9 @@ struct drm_display_mode {
> >   
> >   };
> >   
> > +extern const struct drm_display_mode drm_mode_480i;
> > +extern const struct drm_display_mode drm_mode_576i;
> > +
> >   /**
> >    * DRM_MODE_FMT - printf string for &struct drm_display_mode
> >    */

--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Ivo Totev

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