Re: [PATCH v2 00/33] drm: Analog TV Improvements

["Noralf Trønnes" <noralf@tronnes.org>]

Den 22.09.2022 16.25, skrev Maxime Ripard:
> 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

<snip>

>  drivers/gpu/drm/drm_atomic_state_helper.c       | 128 ++++-
>  drivers/gpu/drm/drm_atomic_uapi.c               |   8 +
>  drivers/gpu/drm/drm_client_modeset.c            |   4 +
>  drivers/gpu/drm/drm_connector.c                 | 111 +++-
>  drivers/gpu/drm/drm_modes.c                     | 658 +++++++++++++++++++++++-
>  drivers/gpu/drm/gud/gud_connector.c             |  12 +-
>  drivers/gpu/drm/i2c/ch7006_drv.c                |   6 +-
>  drivers/gpu/drm/i915/display/intel_tv.c         |   5 +-
>  drivers/gpu/drm/nouveau/dispnv04/tvnv17.c       |   6 +-
>  drivers/gpu/drm/sun4i/sun4i_tv.c                | 148 ++----
>  drivers/gpu/drm/tests/Makefile                  |  16 +-
>  drivers/gpu/drm/tests/drm_client_modeset_test.c | 239 +++++++++
>  drivers/gpu/drm/tests/drm_cmdline_parser_test.c |  67 +++
>  drivers/gpu/drm/tests/drm_kunit_helpers.c       |  54 ++
>  drivers/gpu/drm/tests/drm_kunit_helpers.h       |   9 +
>  drivers/gpu/drm/tests/drm_modes_test.c          | 136 +++++
>  drivers/gpu/drm/vc4/vc4_hdmi.c                  |   2 +-
>  drivers/gpu/drm/vc4/vc4_vec.c                   | 339 ++++++++++--
>  include/drm/drm_atomic_state_helper.h           |   4 +
>  include/drm/drm_connector.h                     |  92 +++-
>  include/drm/drm_mode_config.h                   |  12 +-
>  include/drm/drm_modes.h                         |  17 +

These also needs updating:

Documentation/gpu/kms-properties.csv
Documentation/fb/modedb.rst

Noralf.