On 06/12/24 11:17, Christian König wrote:
Am 06.12.24 um 14:12 schrieb Maíra Canal:
This series introduces a series of clean-ups in BO reservations for the
VC4 driver. Currently, VC4 uses shared fences to track BO reservations as
several other DRM devices. But apart from the DMA reservation objects,
VC4
also attaches seqnos to its BOs with the intention to track if the job
that
uses such BO has finished.
The seqno tracking system was introduced before the DMA reservation
objects
and we ended up lefting it in the code after DMA resv was introduced.
This
is redundant, as we can perfectly track the end of a job with a fence.
Therefore, this series focuses on eliminating the seqnos from the BO.
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.
Just FYI, you duplicated the text somehow :)
Oops, that's a non-native English-speaker trying to write a v2 of a
paragraph :)
Patch Breakdown
===============
* Patch #1: Uses the DRM GEM implementation of
`drm_gem_lock_reservations()`
and `drm_gem_unlock_reservations()` to replace the open-coded
implementation
of this functions by VC4. A straightforward change with no functional
changes.
I actually pushed to remove drm_gem_lock_reservations() in favor of
using the drm_exec object.
It would be nice if you could use that one instead.
Okay, I'll use DRM exec in the next version. I'd appreciate if you could
take a look at the patches that remove the BOs seqnos.
Thanks for comments!
Best Regards,
- Maíra
Regards,
Christian.
* Patch #2: Implements the VC4 wait BO IOCTL using DMA reservations. 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.
* Patch #4: Deletes the now-unused function `vc4_queue_seqno_cb()`.
Best Regards,
- Maíra
Maíra Canal (4):
drm/vc4: Use `drm_gem_lock_reservations()` instead of hard-coding
drm/vc4: Use DMA Resv to implement VC4 wait BO IOCTL
drm/vc4: Remove BOs seqnos
drm/vc4: Remove `vc4_queue_seqno_cb()`
drivers/gpu/drm/vc4/vc4_crtc.c | 22 ++---
drivers/gpu/drm/vc4/vc4_drv.h | 26 ++---
drivers/gpu/drm/vc4/vc4_gem.c | 147 ++++++-----------------------
drivers/gpu/drm/vc4/vc4_validate.c | 11 ---
4 files changed, 48 insertions(+), 158 deletions(-)
