Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755892AbbGUV6S (ORCPT ); Tue, 21 Jul 2015 17:58:18 -0400 Received: from www.linutronix.de ([62.245.132.108]:35406 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752642AbbGUV6Q (ORCPT ); Tue, 21 Jul 2015 17:58:16 -0400 Date: Tue, 21 Jul 2015 23:58:01 +0200 (CEST) From: Thomas Gleixner To: Florian Fainelli cc: Florian Fainelli , Brian Norris , Gregory Fong , bcm-kernel-feedback-list@broadcom.com, linux-kernel@vger.kernel.org, linux-mips@linux-mips.org, Kevin Cernekee , Jason Cooper Subject: Re: [PATCH 1/2] genirq: add chip_{suspend,resume} PM support to irq_chip In-Reply-To: <55AEB91C.1020202@broadcom.com> Message-ID: References: <20150619224123.GL4917@ld-irv-0074> <1434756403-379-1-git-send-email-computersforpeace@gmail.com> <55AE8E5D.8020700@gmail.com> <55AEB91C.1020202@broadcom.com> User-Agent: Alpine 2.11 (DEB 23 2013-08-11) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1912 Lines: 44 On Tue, 21 Jul 2015, Florian Fainelli wrote: > On 21/07/15 14:23, Thomas Gleixner wrote: > > I just read back on the problem report which was mentioned in the > > changelog: > > > > "It's not a problem with patch 7, exactly, it's a problem with the > > irqchip driver which handles the UART interrupt mask (irq-bcm7120-l2.c). > > The problem is that with a trimmed down device tree (such as the one > > found at arch/arm/boot/dts/bcm7445-bcm97445svmb.dtb), none of the child > > interrupts of the 'irq0_intc' node are described -- we don't have device > > tree nodes for them yet -- but we still require saving and restoring the > > forwarding mask (see 'brcm,int-fwd-mask') in order for the UART > > interrupts to continue operating." > > > > So you are trying to work around a flaw in the device tree by adding > > random callbacks to the core kernel? > > Not quite, you could have your interrupt controller node declared in > Device Tree, but have no "interrupts" property referencing it because: > > - the hardware is just not there, but you inherit a common Device Tree > skleten (*.dtsi) > - you could have Device Tree overlays which may or may not be loaded as > a result of finding expansion boards etc... So if no hardware is there which uses any of those interrupts, then WHY is it a problem at all? If it's a requirement that these registers must be restored (once, not per irq), then I can see that it'd be nice to do that from the core. Though that core suspend/resume function is generic chip specific. So it does not make any sense to force it into struct irq_chip because we have no core infrastructure to deal with it. Thanks, tglx -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/