From mboxrd@z Thu Jan 1 00:00:00 1970 From: tglx@linutronix.de (Thomas Gleixner) Date: Mon, 3 Aug 2015 16:36:29 +0200 (CEST) Subject: [PATCH 1/3] clocksource: atmel-st: Remove irq handler when clock event is unused In-Reply-To: <20150803153004.4a74d99a@bbrezillon> References: <1437161608-26782-1-git-send-email-alexandre.belloni@free-electrons.com> <1437161608-26782-2-git-send-email-alexandre.belloni@free-electrons.com> <20150718222308.GA30489@piout.net> <20150720193726.GJ15539@piout.net> <20150802094028.GN12596@twins.programming.kicks-ass.net> <20150803153004.4a74d99a@bbrezillon> Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Mon, 3 Aug 2015, Boris Brezillon wrote: > On Sun, 2 Aug 2015 11:40:28 +0200 > Peter Zijlstra wrote: > > > On Sun, Aug 02, 2015 at 11:10:21AM +0200, Thomas Gleixner wrote: > > > I think Boris Brezillon had implemented it at some point, but it was > > > shot down for reasons I can't remember. > > > > You weren't around at the time.. DT people didn't like it, said they > > didn't like having to make up fake hardware in their DT crap. > > I don't know who was right, but the fact is they won't be inclined to > take such an approach unless the virtual demuxer is not exposed in the > DT, which is almost impossible since irq users are identifying their > irq lines with a phandle to the interrupt controller and an interrupt > id (usually extracted from the datasheet). I really have no idea why DT folks think that virtual devices are not suitable for DT entries. Marks working assumption from the old thread: > This sounds like a DT-workaround for a Linux implementation problem, > and I don't think this the right way to solve your problem. is simply wrong. This has nothing to do with a Linux implementation problem. It's a sensible workaround for braindamaged hardware at the proper abstraction level. > Anyway, below is a solution providing a way to disable specific > handlers without reworking the way we are modeling shared interrupts. > Thomas, I know you were not in favor of the proposed approach, but, > AFAICT, it does not add any conditional path to the interrupt handling > path (which, IIRC, was one of your requirements), and is simple enough > to be used by people really needing it. > > There's probably other drawback I haven't noticed, so please don't > hesitate to share your thoughts. Yes, aside of the bloat, it needs special handling in free_irq() as well. Thanks, tglx