From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752626Ab2GPPF7 (ORCPT ); Mon, 16 Jul 2012 11:05:59 -0400 Received: from acsinet15.oracle.com ([141.146.126.227]:49664 "EHLO acsinet15.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751432Ab2GPPF5 (ORCPT ); Mon, 16 Jul 2012 11:05:57 -0400 Date: Mon, 16 Jul 2012 10:57:09 -0400 From: Konrad Rzeszutek Wilk To: Stefano Stabellini Cc: "linux-kernel@vger.kernel.org" , "xen-devel@lists.xensource.com" , Ian Campbell , "Tim (Xen.org)" Subject: Re: [PATCH WIP 6/6] xen/arm: enable evtchn irqs Message-ID: <20120716145709.GB552@phenom.dumpdata.com> References: <1340381685-22529-1-git-send-email-stefano.stabellini@eu.citrix.com> <1340381685-22529-6-git-send-email-stefano.stabellini@eu.citrix.com> <20120709144005.GA12102@phenom.dumpdata.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Source-IP: acsinet22.oracle.com [141.146.126.238] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jul 13, 2012 at 06:14:33PM +0100, Stefano Stabellini wrote: > On Mon, 9 Jul 2012, Konrad Rzeszutek Wilk wrote: > > On Fri, Jun 22, 2012 at 05:14:45PM +0100, Stefano Stabellini wrote: > > > On ARM irqs are not enabled by default: > > > > Which IRQs? Xen IRQs? Linux IRQs? > > Linux IRQs > > > > > - call enable_percpu_irq for IRQ_EVTCHN_CALLBACK; > > > > Why do we want to do that? > > drivers are supposed to call enable_irq after request_irq, however on > x86 we could get away without it because Linux irqs are enabled by > default (see below) > > > > > - set the IRQF_VALID flag for the other irqs bound to evtchns. It causes > > > IRQ_NOAUTOEN to be set and as a consequence irq_unmask is going to be > > > called when a xenbus driver calls request_irq. > > > > Can you explain in more details why we need that? > > If _IRQ_NOAUTOEN is set, irq_settings_can_autoenable returns false and > __setup_irq doesn't call irq_startup. > > IRQ_NOAUTOEN is set by default by set_irq_flags on ARM, but not on x86. OK, please include those questions/answers in the git commit and repost. > > > > > > Signed-off-by: Stefano Stabellini > > > --- > > > drivers/xen/events.c | 3 +++ > > > 1 files changed, 3 insertions(+), 0 deletions(-) > > > > > > diff --git a/drivers/xen/events.c b/drivers/xen/events.c > > > index 0132505..ca92755 100644 > > > --- a/drivers/xen/events.c > > > +++ b/drivers/xen/events.c > > > @@ -53,6 +53,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > > > > /* > > > * This lock protects updates to the following mapping and reference-count > > > @@ -827,6 +828,7 @@ int bind_evtchn_to_irq(unsigned int evtchn) > > > > > > xen_irq_info_evtchn_init(irq, evtchn); > > > } > > > + set_irq_flags(irq, IRQF_VALID); > > > > > > out: > > > mutex_unlock(&irq_mapping_update_lock); > > > @@ -1751,6 +1753,7 @@ int __init xen_init_IRQ_arm(void) > > > if (rc) { > > > printk(KERN_ERR "Error requesting IRQ %d\n", IRQ_EVTCHN_CALLBACK); > > > } > > > + enable_percpu_irq(IRQ_EVTCHN_CALLBACK, 0); > > > return rc; > > > } > > > core_initcall(xen_init_IRQ_arm); > > > -- > > > 1.7.2.5 > > > > > > -- > > > 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/ > >