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

Mark Brown
2019-12-11T10:47:42Z

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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.

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