From mboxrd@z Thu Jan 1 00:00:00 1970 From: Thomas Gleixner Subject: Re: [PATCH for 4.12] Revert "pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip" Date: Tue, 27 Jun 2017 15:06:26 +0200 (CEST) Message-ID: References: <20170517225634.GA11404@google.com> <20170527021900.GA119873@google.com> <20170623205911.GA143883@google.com> <20170627000622.GA63039@google.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Sender: linux-pm-owner@vger.kernel.org To: Brian Norris Cc: Heiko Stuebner , Linus Walleij , linux-rockchip@lists.infradead.org, Julia Cartwright , LKML , linux-gpio@vger.kernel.org, John Keeping , linux-pm@vger.kernel.org, Doug Anderson , "Paul E. McKenney" , Peter Zijlstra , Tony Lindgren , "David.Wu" , =?ISO-2022-JP?Q?'=1B$B2+Es=1B=28J'?= List-Id: linux-gpio@vger.kernel.org On Tue, 27 Jun 2017, Thomas Gleixner wrote: > That aside, looking at the commit which caused this discussion: > > 88bb94216f59e pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip > > I assume (the changelog lacks details) that the patch want's to avoid a > might sleep splat from the irq callbacks caused by the regmap spinlock, > which gets converted into a sleeping lock on RT. It does this by abusing > the irq_bus_lock() mechanism, which is wrong to begin with. > > The only irq chip function which uses the regmap magic is the > irq_set_type() callback. Now, I have a hard time to understand (though I'm > no regmap/pinctrl expert) why that regmap stuff needs to be called in the > first place. The level and the polarity are programmed via: > > writel_relaxed(level, gc->reg_base + GPIO_INTTYPE_LEVEL); > writel_relaxed(polarity, gc->reg_base + GPIO_INT_POLARITY); > > Why needs the regmap machinery to be invoked there? The GPIO is already > muxed and configured as interrupt, otherwise none of the irq functions > could be invoked. Hmm? That said, the commit should be reverted and the issue needs to analyzed proper. We still need the RCU -> SCRU conversion, but that's a different problem. Thanks, tglx