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Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown

From	Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Newsgroups	linux.kernel
Subject	Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown
Date	2015-08-06 16:00 +0200
Message-ID	<pUtSa-2in-9@gated-at.bofh.it> (permalink)
References	(4 earlier) <pTrfI-uN-17@gated-at.bofh.it> <pTtKy-4bA-13@gated-at.bofh.it> <pTJ2Y-1c2-49@gated-at.bofh.it> <pUst5-oN-21@gated-at.bofh.it> <pUsCK-zY-21@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On 08/06/2015 02:31 PM, Sebastian Andrzej Siewior wrote:

Hi Peter,

>> I'll look at/test this this weekend, ok?
> 
> Sure. I'm currently re-spinning the patches so have everything in
> proper pieces. While at it I will take a look at x_char.

So now that I actually look at it. If I read this right, we never send
the x_char if the TX-DMA never fails to do its job. The comment above
uart_send_xchar() says it is high priority. What do you suggest, wait
until the transfer completes, send the x_char _or_ pause the transfer
send that byte and then send the byte?
In both cases we have to wait until for the FIFO-empty interrupt to
make sure we don't overrun that TX-FIFO.

I *think* waiting until the transfer completes would be simpler but it
is not necessarily high priority.

>> Regards,
>> Peter Hurley

Sebastian
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Thread

Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown Peter Hurley <peter@hurleysoftware.com> - 2015-08-06 14:30 +0200
  Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2015-08-06 14:40 +0200
    Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2015-08-06 16:00 +0200
      Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown Peter Hurley <peter@hurleysoftware.com> - 2015-08-06 20:30 +0200
        Re: [PATCH 3/3] serial: 8250: omap: restore registers on shutdown Charles Manning <cdhmanning@gmail.com> - 2015-08-07 02:50 +0200

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