On Wed, Jan 13, 2021 at 11:52 AM Veera Sundaram Sankaran veeras@codeaurora.org wrote:
Some drivers have hardware capability to get the precise HW timestamp of certain events based on which the fences are triggered. The delta between the event HW timestamp & current HW reference timestamp can be used to calculate the timestamp in kernel's CLOCK_MONOTONIC time domain. This allows it to set accurate timestamp factoring out any software and IRQ latencies. Add a timestamp variant of fence signal function, dma_fence_signal_timestamp to allow drivers to update the precise timestamp for fences.
Changes in v2:
- Add a new fence signal variant instead of modifying fence struct
Changes in v3:
- Add timestamp domain information to commit-text and
dma_fence_signal_timestamp documentation
Signed-off-by: Veera Sundaram Sankaran veeras@codeaurora.org
Looks ok to me, also did some brief testing w/ AOSP and didn't see any regressions.
Reviewed-by: John Stultz john.stultz@linaro.org
thanks -john