Re: Linux 3.15: SPARC serial console regression

[Thomas Bogendoerfer]

On Sun, Jun 15, 2014 at 08:56:35PM +0200, Sam Ravnborg wrote:
> On Tue, Jun 10, 2014 at 05:20:08PM -0400, Peter Hurley wrote:
> > On 06/10/2014 03:24 PM, Sam Ravnborg wrote:
> > >>From: Peter Hurley <peter@xxxxxxxxxxxxxxxxxx>
> > >>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@xxxxxx> 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@xxxxxxxxxxxx> 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.

ip22zilog.c is also broken (clone of sunzilog).

Thomas.

-- 
Crap can work. Given enough thrust pigs will fly, but it's not necessarily a
good idea.                                                [ RFC1925, 2.3 ]
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