Date:   Mon, 21 Nov 2022 15:51:26 +0100
From:   Daniel Vetter <daniel@...ll.ch>
To:     Maxime Ripard <maxime@...no.tech>
Cc:     Samuel Holland <samuel@...lland.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Maxime Ripard <mripard@...nel.org>,
        Ben Skeggs <bskeggs@...hat.com>, Chen-Yu Tsai <wens@...e.org>,
        David Airlie <airlied@...ux.ie>,
        Jani Nikula <jani.nikula@...ux.intel.com>,
        Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>,
        Emma Anholt <emma@...olt.net>,
        Karol Herbst <kherbst@...hat.com>,
        Lyude Paul <lyude@...hat.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Daniel Vetter <daniel@...ll.ch>,
        Dave Stevenson <dave.stevenson@...pberrypi.com>,
        Hans de Goede <hdegoede@...hat.com>,
        nouveau@...ts.freedesktop.org, intel-gfx@...ts.freedesktop.org,
        Noralf Trønnes <noralf@...nnes.org>,
        dri-devel@...ts.freedesktop.org,
        Mateusz Kwiatkowski <kfyatek+publicgit@...il.com>,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-sunxi@...ts.linux.dev, Dom Cobley <dom@...pberrypi.com>,
        Phil Elwell <phil@...pberrypi.com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>
Subject: Re: [PATCH v10 00/19] drm: Analog TV Improvements

On Thu, Nov 17, 2022 at 10:28:43AM +0100, Maxime Ripard wrote:
> Hi,
> 
> 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.
> 
> The named modes support were initially introduced to allow to specify the
> analog TV mode to be used.
> 
> However, this was causing multiple issues:
> 
>   * 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;
> 
>   * Figuring that out wasn't really easy, since the video= 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;
> 
>   * 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);
> 
>   * 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.
> 
>   * Even though that property was generic, its possible values were
>     specific to each drivers, which made some generic support difficult.
> 
> Thus, I chose to tackle in multiple steps:
> 
>   * A new TV mode property was introduced, with generic values, each driver
>     reporting through a bitmask what standard it supports to the userspace;
> 
>   * 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;
> 
>   * 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;
> 
>   * 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;
> 
> Unit tests were created along the way.
> 
> One can switch from NTSC to PAL now using (on vc4)
> 
> modetest -M vc4  -s 53:720x480i -w 53:'TV mode':1 # NTSC
> modetest -M vc4  -s 53:720x576i -w 53:'TV mode':4 # PAL
> 
> Let me know what you think,
> Maxime

Maxime asked me to drop an Ack-in-principle on this, and I'm not sure I
have any useful input here with my utter lack of understanding for TV
things (I never even had one in my entire life, that's how much I don't
care). But it seems to check all the design boxes around solving annoying
uapi/kms-config issues properly, so

Acked-in-principle-or-something-like-that-by: Daniel Vetter <daniel.vetter@...ll.ch>

Cheers, Daniel

> 
> To: David Airlie <airlied@...ux.ie>
> To: Daniel Vetter <daniel@...ll.ch>
> To: Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>
> To: Maxime Ripard <mripard@...nel.org>
> To: Thomas Zimmermann <tzimmermann@...e.de>
> To: Emma Anholt <emma@...olt.net>
> To: Jani Nikula <jani.nikula@...ux.intel.com>
> To: Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>
> To: Rodrigo Vivi <rodrigo.vivi@...el.com>
> To: Tvrtko Ursulin <tvrtko.ursulin@...ux.intel.com>
> To: Ben Skeggs <bskeggs@...hat.com>
> To: Karol Herbst <kherbst@...hat.com>
> To: Lyude Paul <lyude@...hat.com>
> To: Chen-Yu Tsai <wens@...e.org>
> To: Jernej Skrabec <jernej.skrabec@...il.com>
> To: Samuel Holland <samuel@...lland.org>
> Cc: Geert Uytterhoeven <geert@...ux-m68k.org>
> Cc: Mateusz Kwiatkowski <kfyatek+publicgit@...il.com>
> Cc: "Noralf Trønnes" <noralf@...nnes.org>
> Cc: Dave Stevenson <dave.stevenson@...pberrypi.com>
> Cc: Dom Cobley <dom@...pberrypi.com>
> Cc: Phil Elwell <phil@...pberrypi.com>
> Cc: <dri-devel@...ts.freedesktop.org>
> Cc: linux-kernel@...r.kernel.org
> Cc: intel-gfx@...ts.freedesktop.org
> Cc: nouveau@...ts.freedesktop.org
> Cc: linux-arm-kernel@...ts.infradead.org
> Cc: linux-sunxi@...ts.linux.dev
> Cc: Hans de Goede <hdegoede@...hat.com>
> Signed-off-by: Maxime Ripard <maxime@...no.tech>
> 
> ---
> Changes in v10:
> - Rebase on top of drm-misc-next-2022-11-17
> - Fix checkpatch issues
> - Add missing MODULE_* macros
> - Link to v9: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v9-0-24b168e5bcd5@cerno.tech
> 
> Changes in v9:
> - Rename some tests, switch to kunit_test_suite and parameterized tests where
>   relevant
> - Document the valid named modes
> - Link to v8: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v8-0-09ce1466967c@cerno.tech
> 
> Changes in v8:
> - Changed slightly the helper API to pass in the features
> - Removed unused tv_mode_support function
> - Removed mode name match in _pick_cmdline_mode
> - Added unit tests to the get_modes helper
> - Collected Noralf and Mateusz tags
> - Rebased on drm-misc-next-2022-11-10
> - Link to v7: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v7-0-7072a478c6b3@cerno.tech
> 
> Changes in v7:
> - Switch to another implementation of get_modes from Noralf
> - Made more checks in VEC's atomic_check
> - Fixed typo in a commit log
> - Checked for tv_mode_specified in drm_mode_parse_command_line_for_connector
> - Rebased on drm-misc-next-2022-11-03
> - Link to v6: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v6-0-e7792734108f@cerno.tech
> 
> Changes in v6:
> - Add and convert to a new get_modes helper to create the PAL and NTSC modes in
>   the proper order, with the right preferred mode flag, depending on the driver
>   capabilities and defaults.
> - Support PAL60
> - Renamed tests to be consistent with DRM tests naming convention
> - Simplified a bit the named mode parsing code
> - Add a tv_mode_specified field
> - Return 0 in get_modes implementations instead of error codes
> - Link to v5: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v5-0-d841cc64fe4b@cerno.tech
> 
> Changes in v5:
> - Dropped TV Standard documentation removal
> - Switched the TV Mode documentation from CSV to actual documentation
> - Switched to kunit assertions where possible
> - Switched to KUNIT_ASSERT_NOT_NULL instead of KUNIT_ASSERT_PTR_NE(..., NULL)
> - Shuffled a bit the introduction of drm_client_modeset_connector_get_modes between patches
> - Renamed tv_mode_names to legacy_tv_mode_names
> - Removed the count variable in sun4i_tv_comp_get_modes
> - Rebased on top of current drm-misc-next
> - Link to v4: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v4-0-60d38873f782@cerno.tech
> 
> Changes in v4:
> - Removed the unused TV Standard property documentation
> - Added the TV Mode property documentation to kms-properties.csv
> - Fixed the documentation of drm_mode_create_tv_properties()
> - Removed DRM_MODE_TV_MODE_NONE
> - Reworded the line length check comment in drm_mode_analog_tv tests
> - Switched to HZ_PER_KHZ in drm_mode_analog_tv tests
> - Reworked drm_mode_analog_tv to fill our mode using the previously computed
>   timings
> - Added the command-line option documentation to modedb.rst
> - Improved the Kunit helpers cleanup
> - Moved the subconnector documentation renaming to the proper patch
> - Added the various review tags
> - Removed the count variable in vc4_vec_connector_get_modes
> - Rebased on drm-misc-next-2022-09-23 and fixed a merge conflict
> - Folded all the named mode parsing improvements in a single patch
> - Link to v3: https://lore.kernel.org/r/20220728-rpi-analog-tv-properties-v2-0-f733a0ed9f90@cerno.tech
> 
> 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 patches
> - Added more checks to the TV atomic_check helper
> - Link to v2: https://lore.kernel.org/dri-devel/20220728-rpi-analog-tv-properties-v2-0-459522d653a7@cerno.tech/
> 
> Changes in v2:
> - Kept the older TV mode property as legacy so we can keep the old drivers functional
> - Renamed the tv_norm property to tv_mode
> - Added a function to create PAL and NTSC compatible display modes
> - Added some helpers to instantiate a mock DRM device in Kunit
> - More Kunit tests
> - Removed the HD analog TV modes
> - Renamed some of the tests
> - Renamed some of the named modes
> - Fixed typos in commit logs
> - Added the various tags
> - Link to v1: https://lore.kernel.org/dri-devel/20220728-rpi-analog-tv-properties-v1-0-3d53ae722097@cerno.tech/
> 
> ---
> Mateusz Kwiatkowski (2):
>       drm/vc4: vec: Check for VEC output constraints
>       drm/vc4: vec: Add support for more analog TV standards
> 
> Maxime Ripard (16):
>       drm/tests: client: Mention that we can't use MODULE_ macros
>       drm/connector: Rename legacy TV property
>       drm/connector: Only register TV mode property if present
>       drm/connector: Rename drm_mode_create_tv_properties
>       drm/connector: Add TV standard property
>       drm/modes: Add a function to generate analog display modes
>       drm/connector: Add a function to lookup a TV mode by its name
>       drm/modes: Introduce the tv_mode property as a command-line option
>       drm/modes: Properly generate a drm_display_mode from a named mode
>       drm/client: Remove match on mode name
>       drm/modes: Introduce more named modes
>       drm/atomic-helper: Add a TV properties reset helper
>       drm/atomic-helper: Add an analog TV atomic_check implementation
>       drm/vc4: vec: Use TV Reset implementation
>       drm/vc4: vec: Convert to the new TV mode property
>       drm/sun4i: tv: Convert to the new TV mode property
> 
> Noralf Trønnes (1):
>       drm/probe-helper: Provide a TV get_modes helper
> 
>  Documentation/fb/modedb.rst                     |   5 +
>  Documentation/gpu/drm-kms.rst                   |   6 +
>  drivers/gpu/drm/drm_atomic_state_helper.c       | 124 ++++++
>  drivers/gpu/drm/drm_atomic_uapi.c               |   4 +
>  drivers/gpu/drm/drm_client_modeset.c            |   4 -
>  drivers/gpu/drm/drm_connector.c                 | 173 +++++++-
>  drivers/gpu/drm/drm_modes.c                     | 544 +++++++++++++++++++++++-
>  drivers/gpu/drm/drm_probe_helper.c              |  82 ++++
>  drivers/gpu/drm/gud/gud_connector.c             |  10 +-
>  drivers/gpu/drm/i2c/ch7006_drv.c                |   8 +-
>  drivers/gpu/drm/i915/display/intel_tv.c         |   4 +-
>  drivers/gpu/drm/nouveau/dispnv04/tvnv17.c       |   6 +-
>  drivers/gpu/drm/sun4i/sun4i_tv.c                | 141 ++----
>  drivers/gpu/drm/tests/Makefile                  |   3 +
>  drivers/gpu/drm/tests/drm_client_modeset_test.c |  91 +++-
>  drivers/gpu/drm/tests/drm_cmdline_parser_test.c |  68 +++
>  drivers/gpu/drm/tests/drm_connector_test.c      |  76 ++++
>  drivers/gpu/drm/tests/drm_modes_test.c          | 145 +++++++
>  drivers/gpu/drm/tests/drm_probe_helper_test.c   | 205 +++++++++
>  drivers/gpu/drm/vc4/vc4_vec.c                   | 342 ++++++++++++---
>  include/drm/drm_atomic_state_helper.h           |   4 +
>  include/drm/drm_connector.h                     |  82 +++-
>  include/drm/drm_mode_config.h                   |  12 +-
>  include/drm/drm_modes.h                         |  17 +
>  include/drm/drm_probe_helper.h                  |   1 +
>  25 files changed, 1959 insertions(+), 198 deletions(-)
> ---
> base-commit: 9a47d2357cc30d13054bb0598f74fd61f2c9fc51
> change-id: 20220728-rpi-analog-tv-properties-0914dfcee460
> 
> Best regards,
> -- 
> Maxime Ripard <maxime@...no.tech>

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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