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: Sat, 24 Jun 2017 11:21:43 +0200 (CEST) Message-ID: References: <20170517225634.GA11404@google.com> <20170527021900.GA119873@google.com> <20170623205911.GA143883@google.com> <20170623224049.GP3721@linux.vnet.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: <20170623224049.GP3721@linux.vnet.ibm.com> Sender: linux-pm-owner@vger.kernel.org To: "Paul E. McKenney" Cc: Brian Norris , 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 , Peter Zijlstra , Tony Lindgren List-Id: linux-gpio@vger.kernel.org On Fri, 23 Jun 2017, Paul E. McKenney wrote: > On Sat, Jun 24, 2017 at 12:12:49AM +0200, Thomas Gleixner wrote: > > which added that RCU locking stuff and thereby broke the long existing > > bus_lock() facility of the interrupt core. > > > > irq_bus_lock/unlock was explicitely made to allow sleeping locks for > > interrupt chips which hang behind slow busses like i2c or spi. It took us > > quite some effort to get this done and that patch broke it permanently. > > > > I'm not sure what to do here. This is an ever recurring issue simply > > because RT requires that sleeping locks can be taken inside rcu locked > > regions. So sooner than later we need a resoilution for that problem. > > The usual advice would be for 4990d4fe327b ("PM / Wakeirq: Add automated > device wake IRQ handling") to use SRCU rather than RCU. Is there some > reason that won't work? I can't see one. So yes, we should rather convert that stuff to SRCU instead of playing ping pong forever. Thanks, tglx