From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ulf Hansson Subject: Re: [PATCH 6/7] ARM: OMAP2+: Improve omap_device error for driver writers Date: Fri, 12 Feb 2016 13:53:34 +0100 Message-ID: References: <1455145370-20301-1-git-send-email-tony@atomide.com> <1455145370-20301-7-git-send-email-tony@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <1455145370-20301-7-git-send-email-tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> Sender: linux-spi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tony Lindgren Cc: linux-omap , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , Alan Stern , Kevin Hilman , Nishanth Menon , "Rafael J . Wysocki" , Tero Kristo , Greg Kroah-Hartman , "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , linux-mmc , linux-serial-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, "linux-spi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Mark Brown , Peter Hurley , Wolfram Sang List-Id: linux-i2c@vger.kernel.org On 11 February 2016 at 00:02, Tony Lindgren wrote: > Drivers using pm_runtime_use_autosuspend() may not get disabled after > -EPROBE_DEFER. On the following device driver probe, hardware state > is different from the PM runtime state causing omap_device to produce > the following error: > > omap_device_enable() called from invalid state 1 > > And with omap_device and omap hardware being picky for PM, this will > block any deeper idle states in hardware. > > Let's add a proper error message so driver writers can easily fix > their drivers for PM. > > In general, the solution is to fix the drivers to follow the PM > runtime documentation: > > 1. For sections of code that needs the device disabled, use > pm_runtime_put_sync_suspend() if pm_runtime_set_autosuspend() has > been set. > > 2. For driver exit code, use pm_runtime_dont_use_autosuspend() before > pm_runtime_put_sync() if pm_runtime_use_autosuspend() has been > set. > > Let's not return with 0 from _od_runtime_resume() as that will > eventually lead into new drivers with broken PM runtime that will > block deeper idle states on omaps. > > Cc: Alan Stern > Cc: Kevin Hilman > Cc: Nishanth Menon > Cc: Rafael J. Wysocki > Cc: Ulf Hansson > Cc: Tero Kristo > Signed-off-by: Tony Lindgren Acked-by: Ulf Hansson Kind regards Uffe > --- > arch/arm/mach-omap2/omap_device.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c > index 0437537..ebd8369 100644 > --- a/arch/arm/mach-omap2/omap_device.c > +++ b/arch/arm/mach-omap2/omap_device.c > @@ -602,8 +602,10 @@ static int _od_runtime_resume(struct device *dev) > int ret; > > ret = omap_device_enable(pdev); > - if (ret) > + if (ret) { > + dev_err(dev, "use pm_runtime_put_sync_suspend() in driver?\n"); > return ret; > + } > > return pm_generic_runtime_resume(dev); > } > -- > 2.7.0 > -- To unsubscribe from this list: send the line "unsubscribe linux-spi" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html From mboxrd@z Thu Jan 1 00:00:00 1970 From: ulf.hansson@linaro.org (Ulf Hansson) Date: Fri, 12 Feb 2016 13:53:34 +0100 Subject: [PATCH 6/7] ARM: OMAP2+: Improve omap_device error for driver writers In-Reply-To: <1455145370-20301-7-git-send-email-tony@atomide.com> References: <1455145370-20301-1-git-send-email-tony@atomide.com> <1455145370-20301-7-git-send-email-tony@atomide.com> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 11 February 2016 at 00:02, Tony Lindgren wrote: > Drivers using pm_runtime_use_autosuspend() may not get disabled after > -EPROBE_DEFER. On the following device driver probe, hardware state > is different from the PM runtime state causing omap_device to produce > the following error: > > omap_device_enable() called from invalid state 1 > > And with omap_device and omap hardware being picky for PM, this will > block any deeper idle states in hardware. > > Let's add a proper error message so driver writers can easily fix > their drivers for PM. > > In general, the solution is to fix the drivers to follow the PM > runtime documentation: > > 1. For sections of code that needs the device disabled, use > pm_runtime_put_sync_suspend() if pm_runtime_set_autosuspend() has > been set. > > 2. For driver exit code, use pm_runtime_dont_use_autosuspend() before > pm_runtime_put_sync() if pm_runtime_use_autosuspend() has been > set. > > Let's not return with 0 from _od_runtime_resume() as that will > eventually lead into new drivers with broken PM runtime that will > block deeper idle states on omaps. > > Cc: Alan Stern > Cc: Kevin Hilman > Cc: Nishanth Menon > Cc: Rafael J. Wysocki > Cc: Ulf Hansson > Cc: Tero Kristo > Signed-off-by: Tony Lindgren Acked-by: Ulf Hansson Kind regards Uffe > --- > arch/arm/mach-omap2/omap_device.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/arch/arm/mach-omap2/omap_device.c b/arch/arm/mach-omap2/omap_device.c > index 0437537..ebd8369 100644 > --- a/arch/arm/mach-omap2/omap_device.c > +++ b/arch/arm/mach-omap2/omap_device.c > @@ -602,8 +602,10 @@ static int _od_runtime_resume(struct device *dev) > int ret; > > ret = omap_device_enable(pdev); > - if (ret) > + if (ret) { > + dev_err(dev, "use pm_runtime_put_sync_suspend() in driver?\n"); > return ret; > + } > > return pm_generic_runtime_resume(dev); > } > -- > 2.7.0 >