Re: [PATCH AUTOSEL 5.4 128/350] spi: pxa2xx: Set controller->max_transfer_size in dma mode

Sasha Levin
2019-12-19T17:35:08Z

On Wed, Dec 11, 2019 at 10:47:38AM +0000, Mark Brown wrote:
>On Tue, Dec 10, 2019 at 04:03:53PM -0500, Sasha Levin wrote:
>> From: Daniel Vetter <daniel.vetter@ffwll.ch>
>>
>> [ Upstream commit b2662a164f9dc48da8822e56600686d639056282 ]
>>
>> In DMA mode we have a maximum transfer size, past that the driver
>> falls back to PIO (see the check at the top of pxa2xx_spi_transfer_one).
>> Falling back to PIO for big transfers defeats the point of a dma engine,
>> hence set the max transfer size to inform spi clients that they need
>> to do something smarter.
>
>This won't fix anything by itself, this asks other code to change how it
>behaves which may or may not work in older kernels.

I'll drop it then, thanks!

--
Thanks,
Sasha