linux-kernel - Re: [PATCH 2/5] PM / Wakeirq: Add automated device wake IRQ handling

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20150519151505.GQ10274@atomide.com>
Date:	Tue, 19 May 2015 08:15:05 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	"Rafael J. Wysocki" <rjw@...ysocki.net>
Cc:	Felipe Balbi <balbi@...com>,
	"Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
	Alan Stern <stern@...land.harvard.edu>,
	Andreas Fenkart <afenkart@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Huiquan Zhong <huiquan.zhong@...el.com>,
	Kevin Hilman <khilman@...nel.org>, NeilBrown <neilb@...e.de>,
	Mika Westerberg <mika.westerberg@...ux.intel.com>,
	Nishanth Menon <nm@...com>,
	Peter Hurley <peter@...leysoftware.com>,
	Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Thomas Gleixner <tglx@...utronix.de>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-serial@...r.kernel.org,
	linux-omap@...r.kernel.org
Subject: Re: [PATCH 2/5] PM / Wakeirq: Add automated device wake IRQ handling

* Rafael J. Wysocki <rjw@...ysocki.net> [150519 06:40]:
> On Monday, May 18, 2015 04:44:01 PM Tony Lindgren wrote:
> > +/**
> > + * handle_threaded_wake_irq - Handler for dedicated wake-up interrupts
> > + * @irq: Device dedicated wake-up interrupt
> > + * @_wirq: Wake IRQ data
> > + *
> > + * Some devices have a separate wake-up interrupt in addition to the
> > + * device IO interrupt. The wake-up interrupts signal that the device
> > + * should be woken up from a idle state. This handler uses device
> > + * specific pm_runtime functions to wake the device and then it's
> > + * up to the device to do whatever it needs to. Note as the device
> > + * may need to restore context and start up regulators, we use a
> > + * threaded IRQ.
> > + *
> > + * Also note that we are not resending the lost device interrupts.
> > + * We assume that the wake-up interrupt just needs to wake-up the
> > + * device, and the device pm_runtime_resume() can deal with the
> > + * situation.
> > + */
> > +static irqreturn_t handle_threaded_wake_irq(int irq, void *_wirq)
> > +{
> > +	struct wake_irq *wirq = _wirq;
> > +
> > +	/* We don't want RPM_ASYNC or RPM_NOWAIT here */
> > +	return pm_runtime_resume(wirq->dev) ? IRQ_NONE : IRQ_HANDLED;
> 
> There are various reasons why pm_runtime_resume() may return error codes and
> some of them don't mean that the interrupt was not legitimate.
> 
> Moreover, it returns 1 if the device is already active, in which case the above
> check won't do any good to us.

OK yeah that check won't work then.
 
> Why not to return IRQ_HANDLED unconditionally from here?

OK

Regards,

Tony
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/