From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tony Lindgren Subject: Re: [PATCH REPOST] gpio: omap: use raw locks for locking Date: Mon, 22 Jun 2015 00:08:21 -0700 Message-ID: <20150622070821.GB4156@atomide.com> References: <20150619170654.GA4937@linutronix.de> <5584547B.9040203@oracle.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from muru.com ([72.249.23.125]:59033 "EHLO muru.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753736AbbFVHIY (ORCPT ); Mon, 22 Jun 2015 03:08:24 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-gpio-owner@vger.kernel.org List-Id: linux-gpio@vger.kernel.org To: Javier Martinez Canillas Cc: santosh shilimkar , Sebastian Andrzej Siewior , Santosh Shilimkar , Kevin Hilman , Linus Walleij , Alexandre Courbot , "linux-omap@vger.kernel.org" , Linux GPIO List * Javier Martinez Canillas [150619 14:57]: > On Fri, Jun 19, 2015 at 7:42 PM, santosh shilimkar > wrote: > > On 6/19/2015 10:06 AM, Sebastian Andrzej Siewior wrote: > >> > >> This patch converts gpio_bank.lock from a spin_lock into a > >> raw_spin_lock. The call path is to access this lock is always under a > >> raw_spin_lock, for instance > >> - __setup_irq() holds &desc->lock with irq off > >> + __irq_set_trigger() > >> + omap_gpio_irq_type() > >> > >> - handle_level_irq() (runs with irqs off therefore raw locks) > >> + mask_ack_irq() > >> + omap_gpio_mask_irq() > >> > >> This fixes the obvious backtrace on -RT. However the locking vs context > >> is not and this is not limited to -RT: > >> - omap_gpio_irq_type() is called with IRQ off and has an conditional > >> call to pm_runtime_get_sync() which may sleep. Either it may happen or > >> it may not happen but pm_runtime_get_sync() should not be called with > >> irqs off. > >> > >> - omap_gpio_debounce() is holding the lock with IRQs off. > >> + omap2_set_gpio_debounce() > >> + clk_prepare_enable() > >> + clk_prepare() this one might sleep. > >> The number of users of gpiod_set_debounce() / gpio_set_debounce() > >> looks low but still this is not good. > >> > >> Signed-off-by: Sebastian Andrzej Siewior > >> --- > > > > Should be safe to do it. > > Acked-by: Santosh Shilimkar > > > > Answered on the wrong thread, sorry for the noise. > > Acked-by: Javier Martinez Canillas Seems OK but looks like this needs updating against current Linux next to apply though. Regards, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in