| Message ID | 20250102-b4-rkisp-noncoherent-v1-1-bba164f7132c@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | media: rkisp1: allow non-coherent video capture buffers | expand |
diff --git a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c index 6dcefd144d5abe358323e37ac6133c6134ac636e..c94f7d1d73a92646457a27da20726ec6f92e7717 100644 --- a/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c +++ b/drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c @@ -1563,6 +1563,7 @@ static int rkisp1_register_capture(struct rkisp1_capture *cap) q->timestamp_flags = V4L2_BUF_FLAG_TIMESTAMP_MONOTONIC; q->lock = &node->vlock; q->dev = cap->rkisp1->dev; + q->allow_cache_hints = 1; ret = vb2_queue_init(q); if (ret) { dev_err(cap->rkisp1->dev,
Currently, the rkisp1 driver always uses coherent DMA allocations for video capture buffers. However, on some platforms, using non-coherent buffers can improve performance, especially when CPU processing of MMAP'ed video buffers is required. For example, on the Rockchip RK3399 running at maximum CPU frequency, the time to memcpy a frame from a 1280x720 XRGB32 MMAP'ed buffer to a malloc'ed userspace buffer decreases from 7.7 ms to 1.1 ms when using non-coherent DMA allocation. CPU usage also decreases accordingly. This change allows userspace to request the allocation of non-coherent buffers. Note that the behavior for existing users will remain unchanged unless they explicitly set the V4L2_MEMORY_FLAG_NON_COHERENT flag when allocating buffers. Signed-off-by: Mikhail Rudenko <mike.rudenko@gmail.com> --- drivers/media/platform/rockchip/rkisp1/rkisp1-capture.c | 1 + 1 file changed, 1 insertion(+) --- base-commit: 40ed9e9b2808beeb835bd0ed971fb364c285d39c change-id: 20241231-b4-rkisp-noncoherent-ad6e7c7a68ba Best regards,