Re: [RFC, PATCHv3 3/3] mmc: sdhci: handle wake-up from runtime_pm

From: Alan Stern <stern@rowland.harvard.edu>
To: Pierre Tardy <tardyp@gmail.com>
Cc: linux-pm@lists.linux-foundation.org, linux-mmc@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: Re: [RFC, PATCHv3 3/3] mmc: sdhci: handle wake-up from runtime_pm
Date: Tue, 1 Mar 2011 15:27:54 -0500 (EST)	[thread overview]
Message-ID: <Pine.LNX.4.44L0.1103011525040.2034-100000__36613.757236819$1299011323$gmane$org@iolanthe.rowland.org> (raw)
In-Reply-To: <AANLkTikt1r3j99_ub0ce3_3snjoDXvR2+x6RxcjGfMK8@mail.gmail.com>

On Tue, 1 Mar 2011, Pierre Tardy wrote:

> >> +     if (pm_runtime_suspended()) {
> >> +             host->waking_up = 1;
> >> +             /* Note that we disable temporarly the interrupt until we do the
> >> +              * resume. If we don't then we'll get constantly interrupted
> >> +              * until we actually resume.
> >> +              *
> >> +              * as the irq is shared, this might not be very friendly to our
> >> +              * irq sharers but the pm_runtime workqueue should really be
> >> +              * called soon.
> >
> > Instead of disabling the IRQ, would it be possible to tell the device
> > to stop generating an interrupt request?
> 
> Well, the device is power gated, so any access to it will cause a bus
> timeout (depending of the platform)

But could you gate the power back on and then turn off the interrupt 
request?

It seems like a foolish design to have an interrupt request that can't
be turned off by an interrupt handler.

Alan Stern