Re: [PATCH v7 14/19] dmaengine: tegra-apb: Keep clock enabled only during of DMA transfer

From: Dmitry Osipenko
Date: Thu Feb 06 2020 - 09:31:52 EST


06.02.2020 16:50, Jon Hunter ÐÐÑÐÑ:
>
> On 02/02/2020 22:28, Dmitry Osipenko wrote:
>> It's a bit impractical to enable hardware's clock at the time of DMA
>> channel's allocation because most of DMA client drivers allocate DMA
>> channel at the time of the driver's probing, and thus, DMA clock is kept
>> always-enabled in practice, defeating the whole purpose of runtime PM.
>>
>> Signed-off-by: Dmitry Osipenko <digetx@xxxxxxxxx>
>> ---
>> drivers/dma/tegra20-apb-dma.c | 35 ++++++++++++++++++++++++-----------
>> 1 file changed, 24 insertions(+), 11 deletions(-)
> What about something like ......
> @@ -581,6 +582,7 @@ static bool handle_continuous_head_request(struct tegra_dma_channel *tdc,
> hsgreq = list_first_entry(&tdc->pending_sg_req, typeof(*hsgreq), node);
> if (!hsgreq->configured) {
> tegra_dma_stop(tdc);
> + pm_runtime_put(tdc->tdma->dev);
> dev_err(tdc2dev(tdc), "Error in DMA transfer, aborting DMA\n");
> tegra_dma_abort_all(tdc);
> return false;

Yes, that it's what you suggested to do in the reply to v6.

Alright, I'll drop v7 patch #13 and add the put to this patch #14.