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

[Sasha Levin]

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