Hi Eugen
On Thu, Feb 17, 2022 at 03:56:33PM +0200, Eugen Hristev wrote:
> During experiments with libcamera, it looks like vb2_is_streaming returns
> true before our start streaming is called.
> Order of operations is streamon -> queue -> start_streaming
> ISC would have started the DMA immediately when a buffer is being added
> to the vbqueue if the queue is streaming.
> It is more safe to start the DMA after the start streaming of the driver is
> called.
> Thus, even if vb2queue is streaming, add the buffer to the dma queue of the
> driver instead of actually starting the DMA process, if the start streaming
> has not been called yet.
> Tho achieve this, we have to use vb2_start_streaming_called instead of
> vb2_is_streaming.
>
> Signed-off-by: Eugen Hristev <eugen.hristev@xxxxxxxxxxxxx>
Reviewed-by: Jacopo Mondi <jacopo@xxxxxxxxxx>
Thanks
j
> ---
> drivers/media/platform/atmel/atmel-isc-base.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/media/platform/atmel/atmel-isc-base.c b/drivers/media/platform/atmel/atmel-isc-base.c
> index db15770d5b88..d2cc6c99984f 100644
> --- a/drivers/media/platform/atmel/atmel-isc-base.c
> +++ b/drivers/media/platform/atmel/atmel-isc-base.c
> @@ -442,7 +442,7 @@ static void isc_buffer_queue(struct vb2_buffer *vb)
>
> spin_lock_irqsave(&isc->dma_queue_lock, flags);
> if (!isc->cur_frm && list_empty(&isc->dma_queue) &&
> - vb2_is_streaming(vb->vb2_queue)) {
> + vb2_start_streaming_called(vb->vb2_queue)) {
> isc->cur_frm = buf;
> isc_start_dma(isc);
> } else
> --
> 2.25.1
>
