Re: [PATCH 4.19 182/267] spi: dw: Return any value retrieved from the dma_transfer callback

[Sasha Levin <sashal@kernel.org>]

On Fri, Jun 26, 2020 at 11:18:00AM -0400, Ralph Siemsen wrote:
>Hi Serge, Pavel, Greg,
>
>On Mon, Jun 22, 2020 at 11:51:21PM +0300, Serge Semin wrote:
>>Hello Pavel
>>
>>On Fri, Jun 19, 2020 at 11:07:19PM +0200, Pavel Machek wrote:
>>
>>>Mainline patch simply changes return value, but code is different in
>>>v4.19, and poll_transfer will now be avoided when dws->dma_mapped. Is
>>>that a problem?
>>
>>Actually no.) In that old 4.19 context it's even better to return straight away
>>no matter what value is returned by the dma_transfer() callback.
>
>This patch changes the return dma_transfer return value from 0 to 1, 
>however it was only done in spi-dw-mid.c func mid_spi_dma_transfer().
>
>There is an identical function in spi-dw-mmio.c that needs the same 
>treatment, otherwise access to the SPI device becomes erratic and even 
>causes kernel to hang. Guess how I found this ;-)
>
>So the following patch is needed as well, at least in 4.9 and 4.19, I 
>did not check/test other versions. Mainline does not need this, since 
>the code seems to have been refactored to avoid the duplication.

Could you add your signed-off-by tag please? :)

-- 
Thanks,
Sasha