Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751843Ab2JLUck (ORCPT ); Fri, 12 Oct 2012 16:32:40 -0400 Received: from mail-da0-f46.google.com ([209.85.210.46]:35508 "EHLO mail-da0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751577Ab2JLUch (ORCPT ); Fri, 12 Oct 2012 16:32:37 -0400 From: Kevin Hilman To: Russell King - ARM Linux Cc: Sourav , Paul Walmsley , Felipe Balbi , gregkh@linuxfoundation.org, tony@atomide.com, linux-kernel@vger.kernel.org, santosh.shilimkar@ti.com, linux-serial@vger.kernel.org, linux-omap@vger.kernel.org, linux-arm-kernel@lists.infradead.org, alan@linux.intel.com Subject: Re: [RFT/PATCH] serial: omap: prevent resume if device is not suspended. Organization: Deep Root Systems, LLC References: <20120925091228.GI31374@n2100.arm.linux.org.uk> <20120925091112.GK9137@arwen.pp.htv.fi> <20120925092118.GJ31374@n2100.arm.linux.org.uk> <87ipas2y4h.fsf@deeprootsystems.com> <50784458.9080806@ti.com> <877gqv7imt.fsf@deeprootsystems.com> <20121012164202.GQ28061@n2100.arm.linux.org.uk> <877gqv4lmt.fsf@deeprootsystems.com> <20121012185426.GS28061@n2100.arm.linux.org.uk> Date: Fri, 12 Oct 2012 13:32:34 -0700 In-Reply-To: <20121012185426.GS28061@n2100.arm.linux.org.uk> (Russell King's message of "Fri, 12 Oct 2012 19:54:26 +0100") Message-ID: <87lifbwhwd.fsf@deeprootsystems.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/23.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2800 Lines: 65 Russell King - ARM Linux writes: > On Fri, Oct 12, 2012 at 10:59:22AM -0700, Kevin Hilman wrote: >> Russell King - ARM Linux writes: >> >> > On Fri, Oct 12, 2012 at 09:35:54AM -0700, Kevin Hilman wrote: >> >> Sourav writes: >> >> > diff --git a/drivers/tty/serial/omap-serial.c >> >> > b/drivers/tty/serial/omap-serial.c >> >> > index 6ede6fd..3fbc7f7 100644 >> >> > --- a/drivers/tty/serial/omap-serial.c >> >> > +++ b/drivers/tty/serial/omap-serial.c >> >> > @@ -1414,6 +1414,7 @@ static int __devinit serial_omap_probe(struct >> >> > platform_device *pdev) >> >> > INIT_WORK(&up->qos_work, serial_omap_uart_qos_work); >> >> > >> >> > platform_set_drvdata(pdev, up); >> >> > + pm_runtime_set_active(&pdev->dev); >> >> >> >> NAK. >> >> >> >> This will obviously break platforms where the UARTs are not active >> >> before driver loads. >> > >> > I thought I had proposed a solution for this issue, which was this >> > sequence: >> > >> > omap_device_enable(dev); >> > pm_runtime_set_active(dev); >> > pm_runtime_enable(dev); >> > >> > Yes, I can understand people not liking the omap_device_enable() >> > there, but I also notice that the email suggesting that never got a >> > reply either - not even a "I tried this and it doesn't work" or "it >> > does work". >> >> Yes, that solution would work (though I didn't actually try it.) >> >> However, we can't use omap_device_enable() in the driver. We're trying >> to clean all the drivers of OMAP-specific APIs. That being said, >> something similar could be done in the device/board init code to ensure >> the UART HW is in the state that the driver is expecting it, but again, >> that would just mask the real problem which is that a (re)init of the >> console UART on 2420/n800 is causing output to disappear. > > See my more expansive suggestion just posted. > > Whatever way, this discrepancy between runtime PM state and actual device > state is what is biting you, and it is that which needs fixing. I'm not conviced (yet) that a mismatch is the root cause. Yes, that's what the author of $SUBJECT patch assumed and stated, but I'm not pursuaded. If it's an improperly configured mux issue, then the UART will break whenever the device is actually omap_device_enable'd, whether in the driver or in the bus layer. Kevin -- 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/