From: maxime@cerno.tech
To: kfyatek+publicgit@gmail.com
Cc: "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>, "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>,
"Dom Cobley" <dom@raspberrypi.com>,
linux-sunxi@lists.linux.dev,
"Dave Stevenson" <dave.stevenson@raspberrypi.com>,
"Noralf Trønnes" <noralf@tronnes.org>,
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>
Subject: Re: [PATCH] drm/vc4: vec: Add support for PAL-60
Date: Thu, 20 Oct 2022 17:34:19 +0200 [thread overview]
Message-ID: <20221020153419.po5jnl3fbt6pv7iq@houat> (raw)
In-Reply-To: <0afdeda7-558e-647f-ef28-1fcd80807c1b@gmail.com>
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On Tue, Oct 18, 2022 at 10:57:04PM +0200, Mateusz Kwiatkowski wrote:
> Hi Maxime,
>
> W dniu 18.10.2022 o 10:31, Maxime Ripard pisze:
> > Hi,
> >
> > On Sun, Oct 16, 2022 at 09:46:49PM +0200, Mateusz Kwiatkowski wrote:
> >> @@ -308,14 +324,15 @@ static const struct vc4_vec_tv_mode vc4_vec_tv_modes[] = {
> >> };
> >>
> >> static inline const struct vc4_vec_tv_mode *
> >> -vc4_vec_tv_mode_lookup(unsigned int mode)
> >> +vc4_vec_tv_mode_lookup(unsigned int mode, u16 htotal)
> >> {
> >> unsigned int i;
> >>
> >> for (i = 0; i < ARRAY_SIZE(vc4_vec_tv_modes); i++) {
> >> const struct vc4_vec_tv_mode *tv_mode = &vc4_vec_tv_modes[i];
> >>
> >> - if (tv_mode->mode == mode)
> >> + if (tv_mode->mode == mode &&
> >> + tv_mode->expected_htotal == htotal)
> >> return tv_mode;
> >
> > Is there any reason we're not using the refresh rate to filter this? It
> > seems more natural to me.
>
> Let me give you an example first.
>
> There are actually two ways to configure PAL-60-ish mode on VC4/VEC:
>
> a) Modeline 13.5 720 734 798 858 480 487 493 525 Interlace, standard registers
> set to VEC_CONFIG0_PAL_M_STD, custom frequency enabled and set to 0x2a098acb;
> Setting the standard registers to "PAL-M" puts the VEC in true 59.94 Hz mode,
> so the video timings are identical as for NTSC (or PAL-M), and the custom
> frequency makes the color subcarrier compatible with regular PAL receivers.
> This is the "true" PAL-60, thanks to the true System M timings.
That's the one I would expect, and I assume we could just do that by
selecting the 480i mode + PAL TV Mode property, right?
> a) Modeline 13.5 720 740 804 864 480 486 492 525 Interlace, standards registers
> set to VEC_CONFIG0_PAL with standard frequency; This is a "fake" PAL-60 mode,
> the refresh rate is actually ~59.524 Hz. Most "NTSC" sets will be able to
> sync with this mode no problem, but the VEC is actually operating in its
> 50 Hz mode - it's just the "premature" vertical sync signal causes it to
> output something that is similar to the 525-line system, however strictly
> speaking non-standard due to lower horizontal sync frequency.
But it's not really clear to me why we should support both.
> This comes down to the fact that:
>
> - When VEC's standard registers are set to VEC_CONFIG0_NTSC_STD or
> VEC_CONFIG0_PAL_M_STD, it operates in the "CCIR System M" mode, expects htotal
> to be exactly 858 pixels (and it will generate horizontal sync pulse every 858
> pixels on its own regardless of what comes out of the PV - so there will be
> garbage on screen if you set it to anything else), and vtotal to be 525 lines.
> It will not accept vtotal that's any higher (it will generate its own vertical
> sync as demanded by System M if not triggered by the PV), but it can be lower
> - resulting in modes that are non-standard, but otherwise valid.
>
> - Likewise, when the registers are set to VEC_CONFIG0_PAL_BDGHI_STD,
> VEC_CONFIG0_PAL_N_STD or VEC_CONFIG0_SECAM_STD (SECAM is a bit special, but
> that's irrelevant here), it operates in the "CCIR System B/D/G/H/I/N" mode,
> and likewise, expects htotal to be exactly 864 pixels (garbage on screen
> otherwise), vtotal limit is 625 lines, etc.
>
> Checking for the refresh rate would only work for standard-compliant modes and
> have the potential of completely breaking on any custom modes. Conversely,
> checking for htotal aligns perfectly with the limitations of the hardware, and
> allows the user to set any modeline that the hardware is able to output with
> any level of sanity.
OK
Thanks!
Maxime
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next prev parent reply other threads:[~2022-10-20 15:34 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20220728-rpi-analog-tv-properties-v5-0-d841cc64fe4b@cerno.tech>
[not found] ` <20220728-rpi-analog-tv-properties-v5-22-d841cc64fe4b@cerno.tech>
2022-10-13 18:23 ` [PATCH v5 22/22] drm/sun4i: tv: Convert to the new TV mode property Jernej Škrabec
2022-10-14 7:38 ` Maxime Ripard
2022-10-15 8:59 ` Jernej Škrabec
[not found] ` <20220728-rpi-analog-tv-properties-v5-1-d841cc64fe4b@cerno.tech>
2022-10-15 15:06 ` [PATCH v5 01/22] drm/tests: Add Kunit Helpers Noralf Trønnes
[not found] ` <20220728-rpi-analog-tv-properties-v5-8-d841cc64fe4b@cerno.tech>
2022-10-16 16:11 ` [PATCH v5 08/22] drm/modes: Move named modes parsing to a separate function Noralf Trønnes
2022-10-18 7:57 ` Maxime Ripard
[not found] ` <20220728-rpi-analog-tv-properties-v5-6-d841cc64fe4b@cerno.tech>
2022-10-16 17:34 ` [PATCH v5 06/22] drm/modes: Add a function to generate analog display modes Mateusz Kwiatkowski
2022-10-18 8:08 ` Maxime Ripard
[not found] ` <20220728-rpi-analog-tv-properties-v5-13-d841cc64fe4b@cerno.tech>
2022-10-16 17:51 ` [PATCH v5 13/22] drm/modes: Introduce the tv_mode property as a command-line option Mateusz Kwiatkowski
2022-10-17 10:21 ` Noralf Trønnes
[not found] ` <20220728-rpi-analog-tv-properties-v5-19-d841cc64fe4b@cerno.tech>
2022-10-16 18:12 ` [PATCH v5 19/22] drm/vc4: vec: Check for VEC output constraints Mateusz Kwiatkowski
2022-10-16 18:16 ` Mateusz Kwiatkowski
2022-10-18 8:27 ` Maxime Ripard
[not found] ` <20220728-rpi-analog-tv-properties-v5-20-d841cc64fe4b@cerno.tech>
2022-10-16 18:52 ` [PATCH v5 20/22] drm/vc4: vec: Convert to the new TV mode property Mateusz Kwiatkowski
2022-10-16 18:56 ` Mateusz Kwiatkowski
2022-10-17 10:31 ` Noralf Trønnes
2022-10-18 10:00 ` Maxime Ripard
[not found] ` <da2b4cb4-5d12-3161-64e3-e87a8cc63e81@gmail.com>
2022-10-20 11:58 ` maxime
2022-10-17 11:39 ` Noralf Trønnes
[not found] ` <20220728-rpi-analog-tv-properties-v5-21-d841cc64fe4b@cerno.tech>
2022-10-16 19:02 ` [PATCH v5 21/22] drm/vc4: vec: Add support for more analog TV standards Mateusz Kwiatkowski
2022-10-16 19:46 ` [PATCH] drm/vc4: vec: Add support for PAL-60 Mateusz Kwiatkowski
2022-10-18 8:31 ` Maxime Ripard
2022-10-18 20:57 ` Mateusz Kwiatkowski
2022-10-20 15:34 ` maxime [this message]
[not found] ` <20220728-rpi-analog-tv-properties-v5-16-d841cc64fe4b@cerno.tech>
2022-10-17 10:36 ` [PATCH v5 16/22] drm/atomic-helper: Add a TV properties reset helper Noralf Trønnes
[not found] ` <20220728-rpi-analog-tv-properties-v5-12-d841cc64fe4b@cerno.tech>
2022-10-17 10:44 ` [PATCH v5 12/22] drm/connector: Add a function to lookup a TV mode by its name Noralf Trønnes
2022-10-18 9:33 ` Maxime Ripard
2022-10-18 12:29 ` Noralf Trønnes
2022-10-19 8:48 ` Maxime Ripard
2022-10-19 10:43 ` Noralf Trønnes
2022-10-20 11:29 ` maxime
[not found] ` <20220728-rpi-analog-tv-properties-v5-7-d841cc64fe4b@cerno.tech>
2022-10-15 16:58 ` [PATCH v5 07/22] drm/client: Add some tests for drm_connector_pick_cmdline_mode() Noralf Trønnes
2022-10-20 7:55 ` Michał Winiarski
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