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Date:   Thu, 22 Sep 2022 16:31:12 +0200
From:   Maxime Ripard <maxime@cerno.tech>
To:     Jernej Skrabec <jernej.skrabec@gmail.com>,
        Rodrigo Vivi <rodrigo.vivi@intel.com>,
        Ben Skeggs <bskeggs@redhat.com>,
        David Airlie <airlied@linux.ie>,
        Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
        Emma Anholt <emma@anholt.net>,
        Karol Herbst <kherbst@redhat.com>,
        Samuel Holland <samuel@sholland.org>,
        Jani Nikula <jani.nikula@linux.intel.com>,
        Thomas Zimmermann <tzimmermann@suse.de>,
        Daniel Vetter <daniel@ffwll.ch>, Lyude Paul <lyude@redhat.com>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
        Chen-Yu Tsai <wens@csie.org>
Cc:     Hans de Goede <hdegoede@redhat.com>, nouveau@lists.freedesktop.org,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        Dave Stevenson <dave.stevenson@raspberrypi.com>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        Phil Elwell <phil@raspberrypi.com>,
        intel-gfx@lists.freedesktop.org,
        Noralf =?utf-8?Q?Tr=C3=B8nnes?= <noralf@tronnes.org>,
        Dom Cobley <dom@raspberrypi.com>, linux-sunxi@lists.linux.dev,
        Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>,
        dri-devel@lists.freedesktop.org
Subject: Re: [PATCH v2 00/33] drm: Analog TV Improvements
Message-ID: <20220922143112.urvqqdino6zqqbsu@houat>
References: <20220728-rpi-analog-tv-properties-v2-0-f733a0ed9f90@cerno.tech>
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Hi,

On Thu, Sep 22, 2022 at 04:25:17PM +0200, Maxime Ripard wrote:
> Here's a series aiming at improving the command line named modes support,
> and more importantly how we deal with all the analog TV variants.
>=20
> The named modes support were initially introduced to allow to specify the
> analog TV mode to be used.
>=20
> However, this was causing multiple issues:
>=20
>   * The mode name parsed on the command line was passed directly to the
>     driver, which had to figure out which mode it was suppose to match;
>=20
>   * Figuring that out wasn't really easy, since the video=3D argument or =
what
>     the userspace might not even have a name in the first place, but
>     instead could have passed a mode with the same timings;
>=20
>   * The fallback to matching on the timings was mostly working as long as
>     we were supporting one 525 lines (most likely NSTC) and one 625 lines
>     (PAL), but couldn't differentiate between two modes with the same
>     timings (NTSC vs PAL-M vs NSTC-J for example);
>=20
>   * There was also some overlap with the tv mode property registered by
>     drm_mode_create_tv_properties(), but named modes weren't interacting
>     with that property at all.
>=20
>   * Even though that property was generic, its possible values were
>     specific to each drivers, which made some generic support difficult.
>=20
> Thus, I chose to tackle in multiple steps:
>=20
>   * A new TV mode property was introduced, with generic values, each driv=
er
>     reporting through a bitmask what standard it supports to the userspac=
e;
>=20
>   * This option was added to the command line parsing code to be able to
>     specify it on the kernel command line, and new atomic_check and reset
>     helpers were created to integrate properly into atomic KMS;
>=20
>   * The named mode parsing code is now creating a proper display mode for
>     the given named mode, and the TV standard will thus be part of the
>     connector state;
>=20
>   * Two drivers were converted and tested for now (vc4 and sun4i), with
>     some backward compatibility code to translate the old TV mode to the
>     new TV mode;
>=20
> Unit tests were created along the way.
>=20
> One can switch from NTSC to PAL now using (on vc4)
>=20
> modetest -M vc4  -s 53:720x480i -w 53:'TV mode':1 # NTSC
> modetest -M vc4  -s 53:720x576i -w 53:'TV mode':4 # PAL
>=20
> Let me know what you think,
> Maxime
>=20
> To: David Airlie <airlied@linux.ie>
> To: Daniel Vetter <daniel@ffwll.ch>
> To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> To: Maxime Ripard <mripard@kernel.org>
> To: Thomas Zimmermann <tzimmermann@suse.de>
> To: Emma Anholt <emma@anholt.net>
> To: Jani Nikula <jani.nikula@linux.intel.com>
> To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> To: Rodrigo Vivi <rodrigo.vivi@intel.com>
> To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> To: Ben Skeggs <bskeggs@redhat.com>
> To: Karol Herbst <kherbst@redhat.com>
> To: Lyude Paul <lyude@redhat.com>
> To: Chen-Yu Tsai <wens@csie.org>
> To: Jernej Skrabec <jernej.skrabec@gmail.com>
> To: Samuel Holland <samuel@sholland.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> Cc: "Noralf Tr=F8nnes" <noralf@tronnes.org>
> Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Cc: Dom Cobley <dom@raspberrypi.com>
> Cc: Phil Elwell <phil@raspberrypi.com>
> Cc: <dri-devel@lists.freedesktop.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: nouveau@lists.freedesktop.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-sunxi@lists.linux.dev
> Cc: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.tech>
>=20
> ---
> Changes in v3:
> - Applied some of the fixes to vc4 and sun4i
> - Renamed the old TV mode property to legacy_mode
> - Fixed a bunch of bisection errors
> - Removed most of the redundant TV modes
> - Added a new None TV mode to not fall back on NTSC by mistake
> - Fixed the mode generation function to match better what is expected
> - Added some logging to the mode generation function
> - Split the improvements to the named mode parsing logic into separate pa=
tches
> - Added more checks to the TV atomic_check helper
> - Link to v2: https://lore.kernel.org/dri-devel/20220728-rpi-analog-tv-pr=
operties-v2-0-459522d653a7@cerno.tech/

Sorry, this is obviously the v3...

Maxime

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