From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Loic Poulain <loic.poulain@intel.com>
Cc: Doug Anderson <dianders@chromium.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Heiko Stuebner <heiko@sntech.de>, Jiri Slaby <jslaby@suse.cz>,
Chris Zhong <zyw@rock-chips.com>,
linux-rockchip@lists.infradead.org,
linux-arm-kernel@lists.infradead.org,
Andrew Bresticker <abrestic@chromium.org>,
mika.westerberg@linux.intel.com,
andriy.shevchenko@linux.intel.com, wens@csie.org,
alan@linux.intel.com, linux-serial@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] serial: 8250_dw: Handle no_console_suspend when uart loses state
Date: Fri, 28 Nov 2014 14:09:29 +0200 [thread overview]
Message-ID: <20141128120929.GC28114@kuha.fi.intel.com> (raw)
In-Reply-To: <5469B828.90401@intel.com>
On Mon, Nov 17, 2014 at 09:56:08AM +0100, Loic Poulain wrote:
> >In certain suspend modes on certain boards the 8250 UART may lose
> >state when the device goes to suspend. If we're using
> >no_console_suspend this can cause lots of problems during resume.
> >
> >Let's cache the basic UART config registers at suspend time and if we
> >notice that the UART loses state (by looking at a canary stored in the
> >scratch register) we'll restore it.
>
> If I'm not wrong, it's already done in acpi_lpss suspend/resume (for
> 8250_dw).
> Commit c78b0830667a7e7c1f0ca65b76b33166a84806b3.
FYI, we are not saving any UART specific registers in acpi_lpss.c nor
any other bus controller's registers that are part of the LPSS block.
We are saving/restoring only the context of lpss specific register
there.
Cheers,
--
heikki
next prev parent reply other threads:[~2014-11-28 12:09 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-15 0:32 [PATCH] serial: 8250_dw: Handle no_console_suspend when uart loses state Doug Anderson
2014-11-17 8:56 ` Loic Poulain
2014-11-17 9:20 ` Heiko Stübner
2014-11-28 12:09 ` Heikki Krogerus [this message]
2014-11-28 12:30 ` Andy Shevchenko
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