From: Maxime Ripard <maxime@cerno.tech>
To: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: "Emma Anholt" <emma@anholt.net>,
"Neil Armstrong" <narmstrong@baylibre.com>,
"David Airlie" <airlied@linux.ie>,
"DRI Development" <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>,
linux-sunxi@lists.linux.dev,
"Martin Blumenstingl" <martin.blumenstingl@googlemail.com>,
"open list:ARM/Amlogic Meson..."
<linux-amlogic@lists.infradead.org>,
"Linux ARM" <linux-arm-kernel@lists.infradead.org>,
"Dom Cobley" <dom@raspberrypi.com>,
"Dave Stevenson" <dave.stevenson@raspberrypi.com>,
"Linux Kernel Mailing List" <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 04/35] drm/modes: Introduce 480i and 576i modes
Date: Wed, 17 Aug 2022 09:53:51 +0200 [thread overview]
Message-ID: <20220817075351.4xpsqdngjgtiqvob@houat> (raw)
In-Reply-To: <CAMuHMdUNLPbjs=usYQBim5FxsrC1oJLuF+3JB7auzHHRoOqavQ@mail.gmail.com>
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On Tue, Aug 16, 2022 at 05:00:38PM +0200, Geert Uytterhoeven wrote:
> Hi Maxime,
>
> On Tue, Aug 16, 2022 at 3:26 PM Maxime Ripard <maxime@cerno.tech> wrote:
> > On Fri, Aug 12, 2022 at 03:18:58PM +0200, Geert Uytterhoeven wrote:
> > > On Fri, Jul 29, 2022 at 6:35 PM Maxime Ripard <maxime@cerno.tech> wrote:
> > > > Multiple drivers (meson, vc4) define the analog TV 525-lines and 625-lines
> > > > modes in the drivers.
> > >
> > > Nit: strictly speaking these are not analog modes, but the digital
> > > variants (ITU-R BT.656 and DVD-Video D1) of NTSC and PAL, using a
> > > 13.5 MHz sampling frequency for pixels.
> > >
> > > In analog modes, the only discrete values are the number of lines, and
> > > the frame/field rate (fixing the horizontal sync rate when combined).
> > >
> > > The number of (in)visible pixels per line depends on the available
> > > bandwidth. In a digital variant (which is anything generated by a
> > > digital computer system), the latter depends on the pixel clock, which
> > > can wildly differ from the 13.5 MHz used in the BT.656 standard. (e.g.
> > > Amiga uses 7.09/14.19/28.38 MHz (PAL) or 7.16/14.32/28.64 MHz (NTSC)).
> > >
> > > So I think we probably need some way to generate a PAL/NTSC-compatible
> > > mode based not only on resolution, but also on pixel clock.
> >
> > This would also fix the comments made by Jani and Thomas, so I quite
> > like the idea of it.
> >
> > I'm struggling a bit to find how would could implement this though.
> >
> > From what you were saying, I guess the prototype would be something like
> >
> > struct drm_display_mode *drm_create_analog_mode(unsigned int pixel_clock,
> > unsigned int lines,
> > unsigned int frame_rate)
> >
> > But I have zero idea on what the implementation would be. Do you have
> > some resources for this you could point me to?
>
> Horizontally, I think you should calculate left/right margins and
> hsync length to yield timings that match those for the BT.656 PAL/NTSC
> modes. I.e. when a 640x512 mode with a pixel clock of 14 MHz is
> requested, you want to calculate left', right', and hslen' for
>
> | <---- left' ---> | <- 640 pixels -> | <---- right' ---> | <--- hslen' --> |
> @ 14 MHz
>
> so they match the timings for left, right, and hslen for
>
> | <--- left ---> | <--- 720 pixels ---> | <--- right ---> | <--- hslen ---> |
> @ 13.5 MHz
>
> As 640 pixels @ 14 MHz are less wide than 720 pixels @ 13.5 MHz,
> you want to make sure to align the center of the visible part.
So I guess in that example if we want to center it, left == right and
left' == right'? What about the sync length?
> Vertically, it's simpler, as the number of lines is discrete.
> You do have to take into account interlace and doublescan, and
> progressive modes with 262/312 lines.
So we only have to deal with 525 and 625 lines total (without taking
interlace and doublescan into account), right?
I guess we still have the same question, we probably want to center it,
so top == bottom, but what about the vsync length?
Maxime
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next prev parent reply other threads:[~2022-08-17 7:54 UTC|newest]
Thread overview: 151+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-29 16:34 [PATCH v1 00/35] drm: Analog TV Improvements Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 01/35] drm/atomic-helper: Rename drm_atomic_helper_connector_tv_reset to avoid ambiguity Maxime Ripard
2022-08-08 12:25 ` Noralf Trønnes
2022-07-29 16:34 ` [PATCH v1 02/35] drm/connector: Rename subconnector state variable Maxime Ripard
2022-08-08 12:26 ` Noralf Trønnes
2022-07-29 16:34 ` [PATCH v1 03/35] drm/atomic: Add TV subconnector property to get/set_property Maxime Ripard
2022-08-08 12:30 ` Noralf Trønnes
2022-08-15 7:35 ` Maxime Ripard
2022-08-15 10:48 ` Noralf Trønnes
2022-07-29 16:34 ` [PATCH v1 04/35] drm/modes: Introduce 480i and 576i modes Maxime Ripard
2022-08-02 13:58 ` Jani Nikula
2022-08-02 14:16 ` Thomas Zimmermann
2022-08-16 11:58 ` Maxime Ripard
2022-08-12 13:18 ` Geert Uytterhoeven
2022-08-16 13:26 ` Maxime Ripard
2022-08-16 15:00 ` Geert Uytterhoeven
2022-08-17 7:53 ` Maxime Ripard [this message]
2022-08-17 8:51 ` Geert Uytterhoeven
2022-08-17 13:14 ` Maxime Ripard
2022-08-17 14:01 ` Geert Uytterhoeven
2022-08-18 12:39 ` Maxime Ripard
2022-08-18 12:57 ` Geert Uytterhoeven
2022-08-18 13:42 ` Maxime Ripard
2022-08-18 15:34 ` Geert Uytterhoeven
2022-08-18 15:46 ` Maxime Ripard
2022-08-18 15:56 ` Geert Uytterhoeven
2022-08-24 16:42 ` Mateusz Kwiatkowski
2022-08-29 13:29 ` Maxime Ripard
2022-08-29 14:14 ` Geert Uytterhoeven
2022-08-29 14:33 ` Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 05/35] drm/connector: Add TV standard property Maxime Ripard
2022-08-08 12:44 ` Noralf Trønnes
2022-08-16 8:26 ` Maxime Ripard
2022-08-16 9:42 ` Noralf Trønnes
2022-08-16 9:49 ` Maxime Ripard
2022-08-16 19:35 ` Noralf Trønnes
2022-08-17 11:46 ` Maxime Ripard
2022-08-17 13:11 ` Noralf Trønnes
2022-08-17 23:23 ` Noralf Trønnes
2022-08-18 15:01 ` Noralf Trønnes
2022-08-18 15:31 ` Maxime Ripard
2022-08-21 11:43 ` Noralf Trønnes
2022-08-26 8:21 ` Maxime Ripard
2022-08-18 15:27 ` Maxime Ripard
2022-08-12 13:25 ` Geert Uytterhoeven
2022-08-16 13:20 ` Maxime Ripard
2022-08-16 13:29 ` Geert Uytterhoeven
2022-08-16 14:11 ` Maxime Ripard
2022-08-16 14:43 ` Geert Uytterhoeven
2022-08-16 15:49 ` Maxime Ripard
2022-08-17 7:31 ` Geert Uytterhoeven
2022-08-17 7:32 ` Geert Uytterhoeven
2022-08-17 7:47 ` Maxime Ripard
2022-08-17 8:35 ` Geert Uytterhoeven
2022-08-17 11:14 ` Maxime Ripard
2022-08-17 13:05 ` Geert Uytterhoeven
2022-08-17 13:18 ` Maxime Ripard
2022-08-17 14:04 ` Geert Uytterhoeven
2022-08-18 14:54 ` Maxime Ripard
2022-08-18 15:20 ` Geert Uytterhoeven
2022-08-18 15:34 ` Maxime Ripard
2022-08-19 9:35 ` Geert Uytterhoeven
2022-08-25 13:39 ` Maxime Ripard
2022-08-20 20:12 ` Noralf Trønnes
2022-08-25 13:44 ` Maxime Ripard
2022-08-25 15:13 ` Noralf Trønnes
2022-08-29 8:28 ` Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 06/35] drm/connector: Only register TV mode property if present Maxime Ripard
2022-08-08 12:49 ` Noralf Trønnes
2022-08-15 10:40 ` Maxime Ripard
2022-08-15 10:49 ` Noralf Trønnes
2022-07-29 16:34 ` [PATCH v1 07/35] drm/modes: Only consider bpp and refresh before options Maxime Ripard
2022-08-12 13:25 ` Geert Uytterhoeven
2022-08-16 12:20 ` Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 08/35] drm/client: Add some tests for drm_connector_pick_cmdline_mode() Maxime Ripard
2022-08-02 10:14 ` Thomas Zimmermann
2022-08-15 8:42 ` Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 09/35] drm/modes: Move named modes parsing to a separate function Maxime Ripard
2022-08-12 13:27 ` Geert Uytterhoeven
2022-08-16 13:46 ` Maxime Ripard
2022-08-16 14:44 ` Geert Uytterhoeven
2022-07-29 16:34 ` [PATCH v1 10/35] drm/modes: Switch to named mode descriptors Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 11/35] drm/modes: Fill drm_cmdline mode from named modes Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 12/35] drmi/modes: Properly generate a drm_display_mode from a named mode Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 13/35] drm/atomic-helper: Add a TV properties reset helper Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 14/35] drm/atomic-helper: Add an analog TV atomic_check implementation Maxime Ripard
2022-07-29 17:16 ` Mateusz Kwiatkowski
2022-08-15 8:30 ` Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 15/35] drm/vc4: vec: Remove empty mode_fixup Maxime Ripard
2022-07-29 16:34 ` [PATCH v1 16/35] drm/vc4: vec: Convert to atomic helpers Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 17/35] drm/vc4: vec: Refactor VEC TV mode setting Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 18/35] drm/vc4: vec: Remove redundant atomic_mode_set Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 19/35] drm/vc4: vec: Fix timings for VEC modes Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 20/35] drm/vc4: vec: Switch for common modes Maxime Ripard
2022-07-29 18:12 ` Mateusz Kwiatkowski
2022-08-16 11:57 ` Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 21/35] drm/vc4: vec: Fix definition of PAL-M mode Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 22/35] drm/vc4: vec: Use TV Reset implementation Maxime Ripard
2022-07-30 3:03 ` kernel test robot
2022-07-29 16:35 ` [PATCH v1 23/35] drm/vc4: vec: Convert to the new TV mode property Maxime Ripard
2022-08-20 17:22 ` Noralf Trønnes
2022-08-24 15:26 ` Maxime Ripard
2022-08-25 13:14 ` Noralf Trønnes
2022-08-29 12:13 ` Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 24/35] drm/vc4: vec: Add support for more analog TV standards Maxime Ripard
2022-07-29 17:55 ` Mateusz Kwiatkowski
2022-08-15 8:37 ` Maxime Ripard
2022-08-24 16:59 ` Mateusz Kwiatkowski
2022-07-29 16:35 ` [PATCH v1 25/35] drm/sun4i: tv: Remove unused mode_valid Maxime Ripard
2022-07-30 9:13 ` Jernej Škrabec
2022-07-29 16:35 ` [PATCH v1 26/35] drm/sun4i: tv: Convert to atomic hooks Maxime Ripard
2022-07-30 9:12 ` Jernej Škrabec
2022-07-29 16:35 ` [PATCH v1 27/35] drm/sun4i: tv: Merge mode_set into atomic_enable Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 28/35] drm/sun4i: tv: Remove useless function Maxime Ripard
2022-07-29 16:35 ` [PATCH v1 29/35] drm/sun4i: tv: Remove useless destroy function Maxime Ripard
2022-07-30 9:14 ` Jernej Škrabec
2022-07-29 16:35 ` [PATCH v1 30/35] drm/sun4i: tv: Rename error label Maxime Ripard
2022-07-30 9:15 ` Jernej Škrabec
2022-07-29 16:35 ` [PATCH v1 31/35] drm/sun4i: tv: Add missing reset assertion Maxime Ripard
2022-07-30 9:16 ` Jernej Škrabec
2022-07-29 16:35 ` [PATCH v1 32/35] drm/sun4i: tv: Convert to the new TV mode property Maxime Ripard
2022-08-28 17:12 ` Noralf Trønnes
2022-07-29 16:35 ` [PATCH v1 33/35] drm/connector: Remove TV modes property Maxime Ripard
2022-07-29 20:06 ` kernel test robot
2022-07-29 20:16 ` kernel test robot
2022-07-29 16:35 ` [PATCH v1 34/35] drm/modes: Introduce the tv_mode property as a command-line option Maxime Ripard
2022-08-12 13:31 ` Geert Uytterhoeven
2022-08-16 13:51 ` Maxime Ripard
2022-08-20 20:18 ` Noralf Trønnes
2022-08-24 15:45 ` Maxime Ripard
2022-08-24 17:08 ` Mateusz Kwiatkowski
2022-08-25 12:41 ` Noralf Trønnes
2022-08-26 6:46 ` Maxime Ripard
2022-08-28 17:06 ` Noralf Trønnes
2022-07-29 16:35 ` [PATCH v1 35/35] drm/modes: Introduce more named modes Maxime Ripard
2022-08-21 16:16 ` Noralf Trønnes
2022-08-25 14:22 ` Maxime Ripard
2022-08-08 13:03 ` [PATCH v1 00/35] drm: Analog TV Improvements Noralf Trønnes
2022-08-21 16:33 ` Noralf Trønnes
2022-08-22 7:48 ` Maxime Ripard
2022-08-22 8:57 ` Mateusz Kwiatkowski
2022-08-25 15:55 ` Maxime Ripard
2022-08-25 16:17 ` Mateusz Kwiatkowski
2022-08-26 4:07 ` Mateusz Kwiatkowski
2022-08-26 8:39 ` Maxime Ripard
2022-08-26 14:56 ` Dom Cobley
2022-08-27 16:11 ` Noralf Trønnes
2022-08-30 21:31 ` kFYatek
2022-08-22 13:21 ` Noralf Trønnes
2022-08-25 16:21 ` Maxime Ripard
2022-08-25 19:36 ` Noralf Trønnes
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