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

From Andy Shevchenko <andy.shevchenko@gmail.com>
Newsgroups linux.kernel
Subject Re: [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on exception
Date 2016-04-08 10:10 +0200
Message-ID <rlzEm-Px-7@gated-at.bofh.it> (permalink)
References <rloSC-YH-5@gated-at.bofh.it> <rloSC-YH-3@gated-at.bofh.it> <rls0a-3bP-13@gated-at.bofh.it>
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On Fri, Apr 8, 2016 at 2:54 AM, Peter Hurley <peter@hurleysoftware.com> 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

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Thread

[PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on exception Andy Shevchenko <andriy.shevchenko@linux.intel.com> - 2016-04-07 22:40 +0200
  Re: [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on  exception Peter Hurley <peter@hurleysoftware.com> - 2016-04-08 02:00 +0200
    Re: [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on exception Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-04-08 10:10 +0200
      Re: [PATCH v1 06/12] serial: 8250_dma: stop ongoing RX DMA on  exception Peter Hurley <peter@hurleysoftware.com> - 2016-04-09 01:30 +0200

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