Re: [PATCH v1 05/35] drm/connector: Add TV standard property

From: "Noralf Trønnes" <noralf@tronnes.org>
To: Maxime Ripard <maxime@cerno.tech>
Cc: "Emma Anholt" <emma@anholt.net>,
	"Neil Armstrong" <narmstrong@baylibre.com>,
	"David Airlie" <airlied@linux.ie>,
	dri-devel@lists.freedesktop.org,
	"Phil Elwell" <phil@raspberrypi.com>,
	"Jerome Brunet" <jbrunet@baylibre.com>,
	"Samuel Holland" <samuel@sholland.org>,
	"Kevin Hilman" <khilman@baylibre.com>,
	"Jernej Skrabec" <jernej.skrabec@gmail.com>,
	"Chen-Yu Tsai" <wens@csie.org>,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	linux-sunxi@lists.linux.dev,
	"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
	linux-amlogic@lists.infradead.org,
	linux-arm-kernel@lists.infradead.org,
	"Dom Cobley" <dom@raspberrypi.com>,
	"Dave Stevenson" <dave.stevenson@raspberrypi.com>,
	linux-kernel@vger.kernel.org,
	"Mateusz Kwiatkowski" <kfyatek+publicgit@gmail.com>,
	"Noralf Trønnes" <noralf@tronnes.org>,
	"Thomas Zimmermann" <tzimmermann@suse.de>
Subject: Re: [PATCH v1 05/35] drm/connector: Add TV standard property
Date: Thu, 25 Aug 2022 17:13:29 +0200	[thread overview]
Message-ID: <863beb42-1012-b38a-0c3d-89b7e035aa82@tronnes.org> (raw)
In-Reply-To: <20220825134408.dioj2lbycl7jm3ld@houat>

Den 25.08.2022 15.44, skrev Maxime Ripard:
> Hi,
> 
> On Sat, Aug 20, 2022 at 10:12:46PM +0200, Noralf Trønnes wrote:
>>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>>> index 1e9996b33cc8..78275e68ff66 100644
>>> --- a/include/drm/drm_connector.h
>>> +++ b/include/drm/drm_connector.h
>>> @@ -143,6 +143,32 @@ enum subpixel_order {
>>>  
>>>  };
>>>  
>>> +#define DRM_MODE_TV_NORM_NTSC_443	(1 << 0)
>>> +#define DRM_MODE_TV_NORM_NTSC_J		(1 << 1)
>>> +#define DRM_MODE_TV_NORM_NTSC_M		(1 << 2)
>>> +#define DRM_MODE_TV_NORM_PAL_60		(1 << 3)
>>> +#define DRM_MODE_TV_NORM_PAL_B		(1 << 4)
>>> +#define DRM_MODE_TV_NORM_PAL_D		(1 << 5)
>>> +#define DRM_MODE_TV_NORM_PAL_G		(1 << 6)
>>> +#define DRM_MODE_TV_NORM_PAL_H		(1 << 7)
>>> +#define DRM_MODE_TV_NORM_PAL_I		(1 << 8)
>>> +#define DRM_MODE_TV_NORM_PAL_M		(1 << 9)
>>> +#define DRM_MODE_TV_NORM_PAL_N		(1 << 10)
>>> +#define DRM_MODE_TV_NORM_PAL_NC		(1 << 11)
>>> +#define DRM_MODE_TV_NORM_SECAM_60	(1 << 12)
>>> +#define DRM_MODE_TV_NORM_SECAM_B	(1 << 13)
>>> +#define DRM_MODE_TV_NORM_SECAM_D	(1 << 14)
>>> +#define DRM_MODE_TV_NORM_SECAM_G	(1 << 15)
>>> +#define DRM_MODE_TV_NORM_SECAM_K	(1 << 16)
>>> +#define DRM_MODE_TV_NORM_SECAM_K1	(1 << 17)
>>> +#define DRM_MODE_TV_NORM_SECAM_L	(1 << 18)
>>> +#define DRM_MODE_TV_NORM_HD480I		(1 << 19)
>>> +#define DRM_MODE_TV_NORM_HD480P		(1 << 20)
>>> +#define DRM_MODE_TV_NORM_HD576I		(1 << 21)
>>> +#define DRM_MODE_TV_NORM_HD576P		(1 << 22)
>>> +#define DRM_MODE_TV_NORM_HD720P		(1 << 23)
>>> +#define DRM_MODE_TV_NORM_HD1080I	(1 << 24)
>>> +
>>
>> This is an area where DRM overlaps with v4l2, see:
>> - include/dt-bindings/display/sdtv-standards.h
>> - v4l2_norm_to_name()
>>
>> Maybe we should follow suit, but if we do our own thing please mention
>> why in the commit message.
> 
> Are you suggesting that we'd share that definition with v4l2?
> 

If possible, yes.

> I've tried to share some code in the past between v4l2 and DRM, and it
> got completely shut down so it's not something I'd like to try again, if
> possible.
> 

But that is a good enough reason not to do so. I just got the impression
from some of Laurent's emails a while back that there was some
cooperativ atmosphere, but I might be mistaken in my reading/understanding.

It is ofc possible to just copy the values from sdtv-standards.h, but I
see that hd* is missing from that list, so not sure if there's much
point if it has to be extended without changing the source.

We can at least use the names from v4l2_norm_to_name(), but from a quick
look it seems you already do so.

Noralf.