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[v10,00/19] drm: Analog TV Improvements

Message ID 20220728-rpi-analog-tv-properties-v10-0-256dad125326@cerno.tech (mailing list archive)
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Series drm: Analog TV Improvements | expand

Message

Maxime Ripard Nov. 17, 2022, 9:28 a.m. UTC
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

To: David Airlie <airlied@linux.ie>
To: Daniel Vetter <daniel@ffwll.ch>
To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
To: Maxime Ripard <mripard@kernel.org>
To: Thomas Zimmermann <tzimmermann@suse.de>
To: Emma Anholt <emma@anholt.net>
To: Jani Nikula <jani.nikula@linux.intel.com>
To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
To: Rodrigo Vivi <rodrigo.vivi@intel.com>
To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
To: Ben Skeggs <bskeggs@redhat.com>
To: Karol Herbst <kherbst@redhat.com>
To: Lyude Paul <lyude@redhat.com>
To: Chen-Yu Tsai <wens@csie.org>
To: Jernej Skrabec <jernej.skrabec@gmail.com>
To: Samuel Holland <samuel@sholland.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
Cc: Dom Cobley <dom@raspberrypi.com>
Cc: Phil Elwell <phil@raspberrypi.com>
Cc: <dri-devel@lists.freedesktop.org>
Cc: linux-kernel@vger.kernel.org
Cc: intel-gfx@lists.freedesktop.org
Cc: nouveau@lists.freedesktop.org
Cc: linux-arm-kernel@lists.infradead.org
Cc: linux-sunxi@lists.linux.dev
Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Maxime Ripard <maxime@cerno.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,

Comments

Daniel Vetter Nov. 21, 2022, 2:51 p.m. UTC | #1
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@ffwll.ch>

Cheers, Daniel

> 
> To: David Airlie <airlied@linux.ie>
> To: Daniel Vetter <daniel@ffwll.ch>
> To: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
> To: Maxime Ripard <mripard@kernel.org>
> To: Thomas Zimmermann <tzimmermann@suse.de>
> To: Emma Anholt <emma@anholt.net>
> To: Jani Nikula <jani.nikula@linux.intel.com>
> To: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> To: Rodrigo Vivi <rodrigo.vivi@intel.com>
> To: Tvrtko Ursulin <tvrtko.ursulin@linux.intel.com>
> To: Ben Skeggs <bskeggs@redhat.com>
> To: Karol Herbst <kherbst@redhat.com>
> To: Lyude Paul <lyude@redhat.com>
> To: Chen-Yu Tsai <wens@csie.org>
> To: Jernej Skrabec <jernej.skrabec@gmail.com>
> To: Samuel Holland <samuel@sholland.org>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: Mateusz Kwiatkowski <kfyatek+publicgit@gmail.com>
> Cc: "Noralf Trønnes" <noralf@tronnes.org>
> Cc: Dave Stevenson <dave.stevenson@raspberrypi.com>
> Cc: Dom Cobley <dom@raspberrypi.com>
> Cc: Phil Elwell <phil@raspberrypi.com>
> Cc: <dri-devel@lists.freedesktop.org>
> Cc: linux-kernel@vger.kernel.org
> Cc: intel-gfx@lists.freedesktop.org
> Cc: nouveau@lists.freedesktop.org
> Cc: linux-arm-kernel@lists.infradead.org
> Cc: linux-sunxi@lists.linux.dev
> Cc: Hans de Goede <hdegoede@redhat.com>
> Signed-off-by: Maxime Ripard <maxime@cerno.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@cerno.tech>
Maxime Ripard Nov. 24, 2022, 11:49 a.m. UTC | #2
On Mon, Nov 21, 2022 at 03:51:26PM +0100, Daniel Vetter wrote:
> 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@ffwll.ch>

Thanks!

I jumped the gun a bit too fast and forgot to amend the TV property
commit message before pushing it out.

For the record though, that property is usable through xrandr, xorg.conf
or any equivalent compositor mechanism

Maxime