Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756035Ab3DVOuE (ORCPT ); Mon, 22 Apr 2013 10:50:04 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:38540 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754900Ab3DVOuA (ORCPT ); Mon, 22 Apr 2013 10:50:00 -0400 Message-ID: <51754DD7.6040904@ti.com> Date: Mon, 22 Apr 2013 17:48:55 +0300 From: Grygorii Strashko User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130308 Thunderbird/17.0.4 MIME-Version: 1.0 To: Sourav Poddar CC: , , , , , , Subject: Re: [PATCHv2 2/5] driver: serial: omap: prevent runtime PM for "no_console_suspend" References: <1366638237-6880-1-git-send-email-sourav.poddar@ti.com> <1366638237-6880-3-git-send-email-sourav.poddar@ti.com> In-Reply-To: <1366638237-6880-3-git-send-email-sourav.poddar@ti.com> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.167.145.172] X-EXCLAIMER-MD-CONFIG: f9c360f5-3d1e-4c3c-8703-f45bf52eff6b Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2368 Lines: 62 On 04/22/2013 04:43 PM, Sourav Poddar wrote: > The driver manages "no_console_suspend" by preventing runtime PM > during the suspend path, which forces the console UART to stay awake. > > Signed-off-by: Sourav Poddar > --- > drivers/tty/serial/omap-serial.c | 5 ++++- > 1 files changed, 4 insertions(+), 1 deletions(-) > > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c > index 08332f3..640b14e 100644 > --- a/drivers/tty/serial/omap-serial.c > +++ b/drivers/tty/serial/omap-serial.c > @@ -1582,7 +1582,7 @@ static int serial_omap_runtime_suspend(struct device *dev) > struct uart_omap_port *up = dev_get_drvdata(dev); > struct omap_uart_port_info *pdata = dev->platform_data; > > - if (!up) > + if (!up || (!console_suspend_enabled && uart_console(&up->port))) > return -EINVAL; Hi Sourav, No ) You will block Runtime PM for console UART forever, but instead it need to be blocked only during suspend - autosuspend should continue working. But this will be not easy, again, - because System suspend isn't synchronized with Runtime PM (I mean, serial_omap_suspend/resume() may be called from one thread and serial_omap_runtime_suspend/resume() from another at same time). And now, serial_omap_suspend() callback is the only one place where you can detect that system is going to sleep. Personally, i don't believe in such approach (my experiences from K3.4 said me that there will be more problems than benefits). And, I like combination of "no_console_suspend" in bootargs + "ti,no_idle_on_suspend" for console UART in DT, because 1) it's debug option and 2) until smth. will be decided about OMAP OCP Bus it can be used. It's just my opinion. Regards, -grygorii > > if (!pdata) > @@ -1614,6 +1614,9 @@ static int serial_omap_runtime_resume(struct device *dev) > > int loss_cnt = serial_omap_get_context_loss_count(up); > > + if (!console_suspend_enabled && uart_console(&up->port)) > + return -EINVAL; > + > if (loss_cnt < 0) { > dev_err(dev, "serial_omap_get_context_loss_count failed : %d\n", > loss_cnt); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/