Re: [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on exception

From: Andy Shevchenko
Date: Fri Apr 08 2016 - 04:07:54 EST


On Fri, Apr 8, 2016 at 2:54 AM, Peter Hurley <peter@xxxxxxxxxxxxxxxxxx> wrote:
> On 04/07/2016 01:37 PM, Andy Shevchenko wrote:
>> If we get an exeption interrupt. i.e. UART_IIR_RLSI, stop any ongoing RX DMA
>> transfer otherwise it might generates more spurious interrupts and make port
>> unavailable anymore.
>
> Then how to know which rx byte the error is for if dma continues anyway?
> What if there are multiple error bytes?

And how should it work?
We get an interrupt during DMA, if we don't stop DMA it will be racy
with direct readings.

>
>
>> As has been seen on Intel Broxton system:
>
> This system shouldn't be setup for UART DMA imo.

Same approach is done in 8250_omap.

--
With Best Regards,
Andy Shevchenko