Re: [PATCH v7 0/6] drm: Add support for atomic async page-flip

[Helen Koike <helen.koike@collabora.com>]

On 17/10/2023 06:28, André Almeida wrote:
> Hi,
> 
> This work from me and Simon adds support for DRM_MODE_PAGE_FLIP_ASYNC through
> the atomic API. This feature is already available via the legacy API. The use
> case is to be able to present a new frame immediately (or as soon as
> possible), even if after missing a vblank. This might result in tearing, but
> it's useful when a high framerate is desired, such as for gaming.
> 
> Differently from earlier versions, this one refuses to flip if any prop changes
> for async flips. The idea is that the fast path of immediate page flips doesn't
> play well with modeset changes, so only the fb_id can be changed.
> Thanks,
> 	André
> 
> - User-space patch: https://github.com/Plagman/gamescope/pull/595
> - IGT tests: https://gitlab.freedesktop.org/andrealmeid/igt-gpu-tools/-/tree/atomic_async_page_flip
> 
> Changes from v6:
> - Dropped the exception to allow MODE_ID changes (Simon)
> - Clarify what happens when flipping with the same FB_ID (Pekka)
> 
> v6: https://lore.kernel.org/dri-devel/20230815185710.159779-1-andrealmeid@igalia.com/
> 
> Changes from v5:
> - Add note in the docs that not every redundant attribute will result in no-op,
>    some might cause oversynchronization issues.
> 
> v5: https://lore.kernel.org/dri-devel/20230707224059.305474-1-andrealmeid@igalia.com/
> 
> Changes from v4:
>   - Documentation rewrote by Pekka Paalanen
> 
> v4: https://lore.kernel.org/dri-devel/20230701020917.143394-1-andrealmeid@igalia.com/
> 
> Changes from v3:
>   - Add new patch to reject prop changes
>   - Add a documentation clarifying the KMS atomic state set
> 
> v3: https://lore.kernel.org/dri-devel/20220929184307.258331-1-contact@emersion.fr/
> 
> André Almeida (1):
>    drm: Refuse to async flip with atomic prop changes
> 
> Pekka Paalanen (1):
>    drm/doc: Define KMS atomic state set
> 
> Simon Ser (4):
>    drm: allow DRM_MODE_PAGE_FLIP_ASYNC for atomic commits
>    drm: introduce DRM_CAP_ATOMIC_ASYNC_PAGE_FLIP
>    drm: introduce drm_mode_config.atomic_async_page_flip_not_supported
>    amd/display: indicate support for atomic async page-flips on DC
> 
>   Documentation/gpu/drm-uapi.rst                | 47 ++++++++++++
>   drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_dc.c  |  1 +
>   drivers/gpu/drm/drm_atomic_uapi.c             | 75 +++++++++++++++++--
>   drivers/gpu/drm/drm_crtc_internal.h           |  2 +-
>   drivers/gpu/drm/drm_ioctl.c                   |  5 ++
>   drivers/gpu/drm/drm_mode_object.c             |  2 +-
>   .../drm/i915/display/intel_display_driver.c   |  1 +
>   drivers/gpu/drm/nouveau/nouveau_display.c     |  1 +
>   include/drm/drm_mode_config.h                 | 11 +++
>   include/uapi/drm/drm.h                        | 10 ++-
>   include/uapi/drm/drm_mode.h                   |  9 +++
>   11 files changed, 155 insertions(+), 9 deletions(-)
> 

Hello o/

Maybe it is not related (since there are a few years I don't work on 
this) but this reminds me of 
https://yhbt.net/lore/all/20190412125827.5877-1-helen.koike@collabora.com/T/

(just sharing for the sake of communication flow)

Regards,
Helen