From mboxrd@z Thu Jan 1 00:00:00 1970 From: Brian Norris Subject: Re: [PATCH for 4.12] Revert "pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip" Date: Tue, 27 Jun 2017 10:23:09 -0700 Message-ID: <20170627172306.GA91202@google.com> 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: Content-Disposition: inline In-Reply-To: Sender: linux-pm-owner@vger.kernel.org To: Thomas Gleixner 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" , =?utf-8?B?J+m7hOa2myc=?= List-Id: linux-gpio@vger.kernel.org Hi Linus, I'm not sure I follow all of Thomas's suggestions on what should be done in the future yet, but I agree that can be done in parallel: On Tue, Jun 27, 2017 at 03:06:26PM +0200, Thomas Gleixner wrote: > 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. Can we consider this an "ack" for the $subject then? Heiko also gave his approval. How can this get merged? It's running a bit late for 4.12, though it really shouldn't be risky (at least for non-RT stuff that was working warning-free already in 4.11), but a 4.13-rc1 with -stable tag could work as well. I suppose I didn't put a proper 'Fixes' tag (though it should be obvious from the commit message), so here goes: Fixes: 88bb94216f59 ("pinctrl: rockchip: avoid hardirq-unsafe functions in irq_chip") Regards, Brian