Re: [PATCH v5 13/22] drm/modes: Introduce the tv_mode property as a command-line option

From: "Noralf Trønnes" <noralf@tronnes.org>
To: kfyatek+publicgit@gmail.com, Maxime Ripard <maxime@cerno.tech>,
	Karol Herbst <kherbst@redhat.com>,
	Jani Nikula <jani.nikula@linux.intel.com>,
	Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>,
	Daniel Vetter <daniel@ffwll.ch>,
	Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
	David Airlie <airlied@linux.ie>,
	Joonas Lahtinen <joonas.lahtinen@linux.intel.com>,
	Lyude Paul <lyude@redhat.com>, Maxime Ripard <mripard@kernel.org>,
	Emma Anholt <emma@anholt.net>, Chen-Yu Tsai <wens@csie.org>,
	Samuel Holland <samuel@sholland.org>,
	Ben Skeggs <bskeggs@redhat.com>,
	Thomas Zimmermann <tzimmermann@suse.de>,
	Rodrigo Vivi <rodrigo.vivi@intel.com>,
	Jernej Skrabec <jernej.skrabec@gmail.com>
Cc: "Dom Cobley" <dom@raspberrypi.com>,
	linux-sunxi@lists.linux.dev,
	"Dave Stevenson" <dave.stevenson@raspberrypi.com>,
	intel-gfx@lists.freedesktop.org, linux-kernel@vger.kernel.org,
	nouveau@lists.freedesktop.org,
	"Geert Uytterhoeven" <geert@linux-m68k.org>,
	linux-arm-kernel@lists.infradead.org,
	dri-devel@lists.freedesktop.org,
	"Hans de Goede" <hdegoede@redhat.com>,
	"Phil Elwell" <phil@raspberrypi.com>,
	"Noralf Trønnes" <noralf@tronnes.org>
Subject: Re: [PATCH v5 13/22] drm/modes: Introduce the tv_mode property as a command-line option
Date: Mon, 17 Oct 2022 12:21:14 +0200	[thread overview]
Message-ID: <769d2f6e-7fe6-30da-06d8-3c2e9fb9df34@tronnes.org> (raw)
In-Reply-To: <fdeadf0d-8f38-8edf-ae92-e2d9c5aa90b4@gmail.com>

Den 16.10.2022 19.51, skrev Mateusz Kwiatkowski:
> Hi Maxime, Noralf & everyone,
> 
> I'd like to address Noralf here in particular, and refer to these discussions
> from the past:
> 
> - https://lore.kernel.org/linux-arm-kernel/2f607c7d-6da1-c8df-1c02-8dd344a92343@gmail.com/
> - https://lore.kernel.org/linux-arm-kernel/9e76a508-f469-a54d-ecd7-b5868ca99af4@tronnes.org/
> 
>> @@ -2230,20 +2256,22 @@ struct drm_named_mode {
>>  	unsigned int xres;
>>  	unsigned int yres;
>>  	unsigned int flags;
>> +	unsigned int tv_mode;
>>  };
> 
> I saw that you (Noralf) opposed my suggestion about the DRM_MODE_TV_MODE_NONE
> enum value in enum drm drm_connector_tv_mode. I get your argumentation, and I'm
> not gonna argue, but I still don't like the fact that struct drm_named_mode now
> includes a field that is only relevant for analog TV modes, has no "none" value,
> and yet the type is supposed to be generic enough to be usable for other types
> of outputs as well.
> 
> It's true that it can just be ignored (as Maxime mentioned in his response to
> my e-mail linked above), and now the value of 0 corresponds to
> DRM_MODE_TV_MODE_NTSC, which is a rather sane default, but it still feels messy
> to me.
> 
> I'm not gonna force my opinion here, but I wanted to bring your attention to
> this issue, maybe you have some other solution in mind for this problem. Or if
> you don't see that as a problem at all, that's fine, too.
> 

I hadn't looked at this patch in detail before, but you're right this,
together with drm_atomic_helper_connector_tv_reset(), will overwrite
tv.mode unconditionally regardless of tv_mode being present in video= or
not. We need a tv_mode_specified flag like we have for bpp and refresh.

Noralf.