The general approach seems to make sense now I think.
One minor thing which I'm missing is adding support for this to the
dma_fence_array and dma_fence_chain containers.
Regards,
Christian.
Am 07.08.21 um 20:37 schrieb Rob Clark:
From: Rob Clark <robdclark@xxxxxxxxxxxx>
Based on discussion from a previous series[1] to add a "boost" mechanism
when, for example, vblank deadlines are missed. Instead of a boost
callback, this approach adds a way to set a deadline on the fence, by
which the waiter would like to see the fence signalled.
I've not yet had a chance to re-work the drm/msm part of this, but
wanted to send this out as an RFC in case I don't have a chance to
finish the drm/msm part this week.
Original description:
In some cases, like double-buffered rendering, missing vblanks can
trick the GPU into running at a lower frequence, when really we
want to be running at a higher frequency to not miss the vblanks
in the first place.
This is partially inspired by a trick i915 does, but implemented
via dma-fence for a couple of reasons:
1) To continue to be able to use the atomic helpers
2) To support cases where display and gpu are different drivers
[1] https://patchwork.freedesktop.org/series/90331/
v1: https://patchwork.freedesktop.org/series/93035/
v2: Move filtering out of later deadlines to fence implementation
to avoid increasing the size of dma_fence
Rob Clark (5):
dma-fence: Add deadline awareness
drm/vblank: Add helper to get next vblank time
drm/atomic-helper: Set fence deadline for vblank
drm/scheduler: Add fence deadline support
drm/msm: Add deadline based boost support
drivers/dma-buf/dma-fence.c | 20 +++++++
drivers/gpu/drm/drm_atomic_helper.c | 36 ++++++++++++
drivers/gpu/drm/drm_vblank.c | 31 ++++++++++
drivers/gpu/drm/msm/msm_fence.c | 76 +++++++++++++++++++++++++
drivers/gpu/drm/msm/msm_fence.h | 20 +++++++
drivers/gpu/drm/msm/msm_gpu.h | 1 +
drivers/gpu/drm/msm/msm_gpu_devfreq.c | 20 +++++++
drivers/gpu/drm/scheduler/sched_fence.c | 25 ++++++++
drivers/gpu/drm/scheduler/sched_main.c | 3 +
include/drm/drm_vblank.h | 1 +
include/drm/gpu_scheduler.h | 6 ++
include/linux/dma-fence.h | 16 ++++++
12 files changed, 255 insertions(+)
