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From: Sam Ravnborg <sam@ravnborg.org>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>,
	David Miller <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Seth Bollinger <sethb@digi.com>,
	LinusTorvaldstorvalds@linux-foundation.org
Subject: Re: Linux 3.15: SPARC serial console regression
Date: Sun, 15 Jun 2014 20:56:35 +0200	[thread overview]
Message-ID: <20140615185635.GA22577@ravnborg.org> (raw)
In-Reply-To: <53977688.5080802@hurleysoftware.com>

Hi Peter.

On Tue, Jun 10, 2014 at 05:20:08PM -0400, Peter Hurley wrote:
> Hi Sam,
> 
> On 06/10/2014 03:24 PM, Sam Ravnborg wrote:
> >>From: Peter Hurley <peter@hurleysoftware.com>
> >>Date: Mon, 9 Jun 2014 19:21:43 -0400
> >>Subject: [PATCH] serial: sunsab: Test for no tx data on tx restart
> >>
> >>Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c,
> >>'serial_core: Fix conditional start_tx on ring buffer not empty'
> >>exposes an incorrect assumption in sunsab's start_tx method; the
> >>tx ring buffer can, in fact, be empty when restarting tx when
> >>performing flow control.

We have a report that commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c
("serial_core: Fix conditional start_tx on ring buffer not empty")
broke at least one more driver:

    Aaro Koskinen <aaro.koskinen@iki.fi> reported:
    The same problem is present also on PowerPC G5 Xserve (pmac_zilog driver)

And based on code review a third driver is broken:

    Sam Ravnborg <sam@ravnborg.org> reported:
    Can you please take a look at sunzilog.c.
    It looks like the same test is missing in sunzilog_start_tx():

This is a regression so we should either revert the above commit
or review and fix the remaining drivers.

	Sam

WARNING: multiple messages have this Message-ID (diff)
From: Sam Ravnborg <sam@ravnborg.org>
To: Peter Hurley <peter@hurleysoftware.com>
Cc: Aaro Koskinen <aaro.koskinen@iki.fi>,
	David Miller <davem@davemloft.net>,
	linux-kernel@vger.kernel.org, sparclinux@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Seth Bollinger <sethb@digi.com>,
	LinusTorvaldstorvalds@linux-foundation.org
Subject: Re: Linux 3.15: SPARC serial console regression
Date: Sun, 15 Jun 2014 18:56:35 +0000	[thread overview]
Message-ID: <20140615185635.GA22577@ravnborg.org> (raw)
In-Reply-To: <53977688.5080802@hurleysoftware.com>

Hi Peter.

On Tue, Jun 10, 2014 at 05:20:08PM -0400, Peter Hurley wrote:
> Hi Sam,
> 
> On 06/10/2014 03:24 PM, Sam Ravnborg wrote:
> >>From: Peter Hurley <peter@hurleysoftware.com>
> >>Date: Mon, 9 Jun 2014 19:21:43 -0400
> >>Subject: [PATCH] serial: sunsab: Test for no tx data on tx restart
> >>
> >>Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c,
> >>'serial_core: Fix conditional start_tx on ring buffer not empty'
> >>exposes an incorrect assumption in sunsab's start_tx method; the
> >>tx ring buffer can, in fact, be empty when restarting tx when
> >>performing flow control.

We have a report that commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c
("serial_core: Fix conditional start_tx on ring buffer not empty")
broke at least one more driver:

    Aaro Koskinen <aaro.koskinen@iki.fi> reported:
    The same problem is present also on PowerPC G5 Xserve (pmac_zilog driver)

And based on code review a third driver is broken:

    Sam Ravnborg <sam@ravnborg.org> reported:
    Can you please take a look at sunzilog.c.
    It looks like the same test is missing in sunzilog_start_tx():

This is a regression so we should either revert the above commit
or review and fix the remaining drivers.

	Sam

  reply	other threads:[~2014-06-15 18:56 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-06-09 20:59 Linux 3.15: SPARC serial console regression Aaro Koskinen
2014-06-09 20:59 ` Aaro Koskinen
2014-06-09 23:43 ` On 06/09/2014 04:59 PM, Aaro Koskinen wrote:> Hi, Peter Hurley
2014-06-09 23:43   ` Peter Hurley
2014-06-09 23:48 ` FW: Linux 3.15: SPARC serial console regression Peter Hurley
2014-06-09 23:48   ` Peter Hurley
2014-06-10 18:53   ` Aaro Koskinen
2014-06-10 18:53     ` Aaro Koskinen
2014-06-10 19:24   ` Sam Ravnborg
2014-06-10 19:24     ` Sam Ravnborg
2014-06-10 21:20     ` Peter Hurley
2014-06-10 21:20       ` Peter Hurley
2014-06-15 18:56       ` Sam Ravnborg [this message]
2014-06-15 18:56         ` Sam Ravnborg
2014-06-16 14:24         ` Thomas Bogendoerfer
2014-06-16 14:24           ` Thomas Bogendoerfer
2014-06-16 15:37         ` Peter Hurley
2014-06-16 15:37           ` Peter Hurley
2014-06-18  6:19         ` David Miller
2014-06-18  6:19           ` David Miller
2014-06-13 20:18   ` Linux 3.15: " Aaro Koskinen
2014-06-13 20:18     ` Aaro Koskinen
2014-07-06 15:29 ` [PATCH 0/2] fixes for empty tx buffer breakage Peter Hurley
2014-07-06 15:29   ` [PATCH 1/2] serial: Test for no tx data on tx restart Peter Hurley
2014-07-06 15:29   ` [PATCH 2/2] serial: arc_uart: Use uart_circ_empty() for open-coded comparison Peter Hurley
2014-07-10 23:14   ` [PATCH 0/2] fixes for empty tx buffer breakage Greg Kroah-Hartman
2014-07-10 23:12     ` David Miller
2014-07-10 23:29       ` Greg KH

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