From: Greg KH <greg@kroah.com>
To: Stanislav Brabec <sbrabec@suse.cz>
Cc: MyungJoo Ham <myungjoo.ham@samsung.com>, Greg KH <gregkh@suse.de>,
linux-kernel@vger.kernel.org, kyungmin.park@samsung.com,
Alan Cox <alan@linux.intel.com>, Arnd Bergmann <arnd@arndb.de>,
Andr Goddard Rosa <andre.goddard@gmail.com>,
Jason Wang <jason77.wang@gmail.com>,
linux-serial@vger.kernel.org
Subject: Re: [PATCH] Serial: BUGFIX: uart_resume_port has an omitted condition.
Date: Thu, 14 Oct 2010 11:45:11 -0700 [thread overview]
Message-ID: <20101014184511.GA17096@kroah.com> (raw)
In-Reply-To: <1286969205.6082.700.camel@hammer.site>
On Wed, Oct 13, 2010 at 01:26:45PM +0200, Stanislav Brabec wrote:
> On Wed, 13 Oct 2010 15:38:13 +0900, MyungJoo Ham wrote:
> > On Wed, Oct 13, 2010 at 3:26 PM, Greg KH <gregkh@suse.de> wrote:
> > > On Wed, Oct 13, 2010 at 02:58:06PM +0900, MyungJoo Ham wrote:
>
> > > Is this a regression? If so, from what working kernel? Or has this
> > > always been this way?
> >
> > I don't think this is a regression to the previous version. Logically,
> > it's matching the console_stop()-console_start() pair.
>
> This disparity appeared deliberately in 4547be78. If you need
> no_console_suspend and the hardware lets the device in an undefined
> state after resume (i. e. PXA270), you need to call subset of the
> resume, even if the suspend counterpart was not called. Yes, I can
> imagine that it may be a source of problems.
>
> Did you try the latest patches from Jason Wang from linux-serial list?
>
> > Such hang in serial and its mitigation is observed in 2.6.36 at
> > arch/arm/mach-s5pv310 machines. In these machines, it hanged with
> > console_suspend_enabled == 0 every time.
>
> It seems that support for no_console_suspend for all devices is becoming
> more complicated. I guess that a new driver calls (maybe "save_state"
> and "resume_state") or support for no_console_suspend directly in
> drivers may be useful.
Ok, so I'm guessing that this patch is not to be applied then, correct?
thanks,
greg k-h
next prev parent reply other threads:[~2010-10-14 19:02 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-13 5:58 [PATCH] Serial: BUGFIX: uart_resume_port has an omitted condition MyungJoo Ham
2010-10-13 6:26 ` Greg KH
2010-10-13 6:38 ` MyungJoo Ham
2010-10-13 11:26 ` Stanislav Brabec
2010-10-14 18:45 ` Greg KH [this message]
2010-10-14 19:45 ` Stanislav Brabec
2010-10-14 20:05 ` Greg KH
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