Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes

From	Peter Hurley <peter@hurleysoftware.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes
Date	2016-04-11 20:00 +0200
Message-ID	<rmOhX-1e7-1@gated-at.bofh.it> (permalink)
References	<riGsH-2h8-37@gated-at.bofh.it> <rkqts-5H7-9@gated-at.bofh.it> <rmFeG-2HC-19@gated-at.bofh.it>
Organization	linux.* mail to news gateway

Show all headers | View raw

On 04/11/2016 01:18 AM, John Ogness wrote:
> On 2016-04-05, Peter Hurley <peter@hurleysoftware.com> wrote:
>> On 03/31/2016 01:41 AM, John Ogness wrote:
>>> It has been observed that the TX-DMA can stall
>>
>> Does this happen on any other OMAP part besides am335x?
>> I looked back over the LKML history of this and didn't see
>> any other design implicated in this problem.
> 
> I just ran the tests again using 4.6-rc2. I am able to reproduce the
> dma-tx stall with am335x/edma and dra7/sdma.

I thought we already established sdma was not to be used since
the hardware does not actually support pausing without data loss.

http://www.spinics.net/lists/linux-serial/msg18503.html


So I'm wondering if we're carrying all this extra DMA complexity
and workarounds for just am335x?


> Note: To achieve the stall, both the delayed_restore and the
>       rx_dma_broken features of the mainline 8250_omap driver needed to
>       be removed.
> 
> John Ogness
>

Thread

Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-05 06:10 +0200
  Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes John Ogness <john.ogness@linutronix.de> - 2016-04-11 10:20 +0200
    Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-11 20:00 +0200
      Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-04-11 20:40 +0200
        Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-11 22:20 +0200
          Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Sebastian Andrzej Siewior <bigeasy@linutronix.de> - 2016-04-12 19:10 +0200
            Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-12 20:50 +0200
              Re: [PATCH] tty: serial: 8250_omap: do not defer termios changes Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 18:10 +0200
            8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do not  defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-13 01:30 +0200
              Re: 8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do  not defer termios changes) One Thousand Gnomes <gnomes@lxorguk.ukuu.org.uk> - 2016-04-14 17:10 +0200
                Re: 8250 dma issues ( was Re: [PATCH] tty: serial: 8250_omap: do not  defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 20:00 +0200
            omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do not  defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-13 02:10 +0200
              Re: omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do  not defer termios changes) Sekhar Nori <nsekhar@ti.com> - 2016-04-13 13:20 +0200
                Re: omap uart + dma issues (Re: [PATCH] tty: serial: 8250_omap: do  not defer termios changes) Peter Hurley <peter@hurleysoftware.com> - 2016-04-14 03:20 +0200

csiph-web