[PATCH v3 0/3] drm/vc4: Clean-up BO seqnos

[Melissa Wen]

On 20/12/2024 10:37, Maíra Canal wrote:
> This series introduces a series of clean-ups for BO reservations in
> the VC4 driver. Currently, VC4 uses shared fences to track BO
> reservations, similar to many other DRM devices. However, in addition
> to DMA reservation objects, VC4 has been maintaining a separate seqno
> tracking system for BOs to track job completion.
>
> The seqno tracking system was implemented before DMA reservation
> objects and was left in the code after DMA reservation's introduction.
> This approach is now redundant, as job completion can be effectively
> tracked using fences. Consequently, this series focuses on eliminating
> seqnos from the BO implementation.
>
> Patch Breakdown
> ===============
>
> * Patch #1: Uses the DRM Exec to replace the open-coded implementation
> of the functions `drm_gem_lock_reservations()` and
> `drm_gem_unlock_reservations()` in the VC4 driver code. A straightforward
> change with no functional changes.
>
> * Patch #2: Implements the VC4 wait BO IOCTL using DMA Resv Objects.
> The new implementation closely mirrors the V3D approach and removes
> the IOCTL's dependency on BO sequence numbers.
>
> * Patch #3: The central piece of this patchset. It removes `bo->seqno`,
> `bo->write_seqno`, and `exec->bin_dep_seqno` from the driver. As the
> seqno tracking system is redundant, its deletion is relatively
> straightforward. The only notable change is `vc4_async_set_fence_cb()`,
> which now uses `dma_fence_add_callback()` to add the VC4 callback.
This series is:

Reviewed-by: Melissa Wen <mwen at igalia.com>

Thanks!
>
> Changes
> =======
>
> v1 -> v2: https://lore.kernel.org/dri-devel/20241206131706.203324-1-mcanal@igalia.com/T/
>
> * [1/4] Use DRM Exec to replace the (un)lock reservation functions
>          (Christian König)
>
> v2 -> v3: https://lore.kernel.org/dri-devel/20241212202337.381614-1-mcanal@igalia.com/T/
>
> * [1/4] König's A-b (Christian König)
> * [2/4] s/dma_gem_dma_resv_wait/drm_gem_dma_resv_wait (Melissa Wen)
> * [2/4] Use `usecs_to_jiffies()` to calculate the timeout in jiffies
>          (Tvrtko Ursulin)
> * [2/4] Remove -EAGAIN errno from the IOCTL (Tvrtko Ursulin)
> * [3/4] s/vc4_async_page_flip_seqno_complete/vc4_async_page_flip_complete_with_cleanup
>          (Melissa Wen)
> * [3/4] Add `dma_fence_put()` in `vc4_async_page_flip_complete_with_cleanup()`
> * [3/4] Maxime's R-b (Maxime Ripard)
> * [4/4] Squashed to PATCH 3/4 (Melissa Wen)
> * [4/4] Remove `vc4->seqno_cb_list` and `struct vc4_seqno_cb` (Tvrtko Ursulin)
>
> Best Regards,
> - Maíra
>
> ---
>
> Maíra Canal (3):
>    drm/vc4: Use DRM Execution Contexts
>    drm/vc4: Use DMA Resv to implement VC4 wait BO IOCTL
>    drm/vc4: Remove BOs seqnos
>
>   drivers/gpu/drm/vc4/Kconfig        |   1 +
>   drivers/gpu/drm/vc4/vc4_crtc.c     |  33 +++---
>   drivers/gpu/drm/vc4/vc4_drv.h      |  27 -----
>   drivers/gpu/drm/vc4/vc4_gem.c      | 183 ++++++-----------------------
>   drivers/gpu/drm/vc4/vc4_validate.c |  11 --
>   5 files changed, 53 insertions(+), 202 deletions(-)
>