From: "Rafael J. Wysocki" <rjw@rjwysocki.net>
To: Boris Brezillon <boris.brezillon@free-electrons.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Jason Cooper <jason@lakedaemon.net>,
Nicolas Ferre <nicolas.ferre@atmel.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Alexandre Belloni <alexandre.belloni@free-electrons.com>,
Rob Herring <robh+dt@kernel.org>, Pawel Moll <Pawel.Moll@arm.com>,
Ian Campbell <ijc+devicetree@hellion.org.uk>,
Kumar Gala <galak@codeaurora.org>,
"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
"Rafael J. Wysocki" <rafael.j.wysocki@intel.com>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v4 3/5] irqchip: Add DT binding doc for the virtual irq demuxer chip
Date: Wed, 11 Feb 2015 17:42:22 +0100 [thread overview]
Message-ID: <2067295.NbJCftPPli@vostro.rjw.lan> (raw)
In-Reply-To: <20150211171515.55d5066f@bbrezillon>
On Wednesday, February 11, 2015 05:15:15 PM Boris Brezillon wrote:
> On Wed, 11 Feb 2015 15:57:20 +0000
> Mark Rutland <mark.rutland@arm.com> wrote:
>
> > [...]
> >
> > > > > > So for the flag at request time approach to work, all the drivers using
> > > > > > the interrupt would have to flag they're safe in that context.
> > > > >
> > > > > Something like IRQF_"I can share the line with a timer" I guess? That wouldn't
> > > > > hurt and can be checked at request time even.
> > > >
> > > > I guess that would have to imply IRQF_SHARED, so we'd have something
> > > > like:
> > > >
> > > > IRQF_SHARED_SUSPEND_OK - This handler is safe to call spuriously during
> > > > suspend in the case the line is shared. The
> > > > handler will not access unavailable hardware
> > > > or kernel infrastructure during this period.
> > > >
> > > > #define __IRQF_SUSPEND_SPURIOUS 0x00040000
> > > > #define IRQF_SHARED_SUSPEND_OK (IRQF_SHARED | __IRQF_SUSPEND_SPURIOUS)
> > >
> > > What about
> > >
> > > #define __IRQF_TIMER_SIBLING_OK 0x00040000
> > > #define IRQF_SHARED_TIMER_OK (IRQF_SHARED | __IRQF_TIMER_SIBLING_OK)
> > >
> > > The "suspend" part is kind of a distraction to me here, because that really
> > > only is about sharing an IRQ with a timer and the "your interrupt handler
> > > may be called when the device is suspended" part is just a consequence of that.
> >
> > My rationale was that you didn't really care who else was using the IRQ
> > (e.g. the timer); you're just stating that you can survive being called
> > during suspend (which is what the driver may need to check for in the
> > handler if the device happens to be powered down or whatever).
> >
> > So I guess I see it the other way around. This is essentially claiming
> > we can handle sharing with IRQF_NO_SUSPEND rather than IRQF_TIMER.
> >
> > > So IMO it's better to have "TIMER" in the names to avoid encouraging people to
> > > abuse this for other purposes not related to timers.
> >
> > In the end a name is a name, and if you think IRQF_SHARED_TIMER_OK is
> > better I shan't complain.
> >
> > The fundamental issue I'm concerned with is addressed by this approach.
>
> Okay then, is anyone taking care of submitting such a patch (Mark ?) ?
Well, I guess I should take the responsibility for that. :-)
I'll try to cut one later today or tomorrow unless someone else beats me to that.
Rafael
next prev parent reply other threads:[~2015-02-11 16:19 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-29 10:33 [PATCH v4 0/5] ARM: at91: fix irq_pm_install_action WARNING Boris Brezillon
2015-01-29 10:33 ` [PATCH v4 1/5] genirq: Authorize chained handlers to remain disabled when initialized Boris Brezillon
2015-01-29 10:33 ` [PATCH v4 2/5] irqchip: add virtual demultiplexer implementation Boris Brezillon
2015-02-10 15:00 ` Peter Zijlstra
2015-02-10 15:20 ` Boris Brezillon
2015-02-10 15:43 ` [PATCH] genirq: fix virtual irq demuxer related comments Boris Brezillon
2015-02-10 16:14 ` Peter Zijlstra
2015-02-20 16:12 ` Mark Rutland
2015-02-20 16:17 ` Peter Zijlstra
2015-02-10 15:48 ` [PATCH v4 2/5] irqchip: add virtual demultiplexer implementation Mark Rutland
2015-01-29 10:33 ` [PATCH v4 3/5] irqchip: Add DT binding doc for the virtual irq demuxer chip Boris Brezillon
2015-02-10 15:36 ` Mark Rutland
2015-02-10 15:52 ` Boris Brezillon
2015-02-10 16:06 ` Boris Brezillon
2015-02-10 16:16 ` Mark Rutland
2015-02-10 16:20 ` Boris Brezillon
2015-02-10 20:48 ` Mark Rutland
2015-02-11 8:53 ` Boris Brezillon
2015-02-11 11:11 ` Mark Rutland
2015-02-11 12:24 ` Boris Brezillon
2015-02-11 12:36 ` Mark Rutland
2015-02-11 13:38 ` Alexandre Belloni
2015-02-11 13:48 ` Mark Rutland
2015-02-11 14:55 ` Rafael J. Wysocki
2015-02-11 14:43 ` Mark Rutland
2015-02-11 15:17 ` Rafael J. Wysocki
2015-02-11 15:03 ` Boris Brezillon
2015-02-11 15:39 ` Rafael J. Wysocki
2015-02-11 15:23 ` Mark Rutland
2015-02-11 15:12 ` Mark Rutland
2015-02-11 15:51 ` Rafael J. Wysocki
2015-02-11 15:57 ` Mark Rutland
2015-02-11 16:15 ` Boris Brezillon
2015-02-11 16:32 ` Mark Rutland
2015-02-11 16:38 ` Boris Brezillon
2015-02-11 17:17 ` Mark Rutland
2015-02-20 14:22 ` Mark Rutland
2015-02-20 14:53 ` Boris Brezillon
2015-02-20 15:16 ` Mark Rutland
2015-02-23 17:00 ` Boris Brezillon
2015-02-23 18:14 ` Mark Rutland
2015-02-23 20:16 ` Boris Brezillon
2015-02-11 16:42 ` Rafael J. Wysocki [this message]
2015-02-11 16:28 ` Boris Brezillon
2015-02-11 17:13 ` Mark Rutland
2015-02-11 17:29 ` Boris Brezillon
2015-02-12 10:52 ` Mark Rutland
2015-02-12 11:09 ` Boris Brezillon
2015-02-12 11:23 ` Mark Rutland
2015-02-16 9:49 ` Peter Zijlstra
2015-02-16 9:28 ` Peter Zijlstra
2015-02-16 12:23 ` Mark Rutland
2015-02-19 1:16 ` Rafael J. Wysocki
2015-02-19 11:23 ` Mark Rutland
2015-02-19 22:35 ` Rafael J. Wysocki
2015-02-20 10:31 ` Mark Rutland
2015-02-24 1:02 ` Rafael J. Wysocki
2015-02-24 8:42 ` Boris Brezillon
2015-02-11 14:45 ` Boris Brezillon
2015-02-11 14:39 ` Rafael J. Wysocki
2015-02-11 9:11 ` Peter Zijlstra
2015-02-11 11:15 ` Mark Rutland
2015-02-11 14:31 ` Rafael J. Wysocki
2015-02-11 14:14 ` Mark Rutland
2015-02-11 15:07 ` Rafael J. Wysocki
2015-02-11 15:03 ` Mark Rutland
2015-02-11 14:34 ` Rafael J. Wysocki
2015-01-29 10:33 ` [PATCH v4 4/5] ARM: at91/dt: select VIRT_IRQ_DEMUX for all at91 SoCs Boris Brezillon
2015-01-29 10:33 ` [PATCH v4 5/5] ARM: at91/dt: define a virtual irq demultiplexer chip connected on irq1 Boris Brezillon
2015-02-09 15:47 ` [PATCH v4 0/5] ARM: at91: fix irq_pm_install_action WARNING Boris Brezillon
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