From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933457Ab2GMRPT (ORCPT ); Fri, 13 Jul 2012 13:15:19 -0400 Received: from smtp.eu.citrix.com ([62.200.22.115]:22826 "EHLO SMTP.EU.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932301Ab2GMRPR (ORCPT ); Fri, 13 Jul 2012 13:15:17 -0400 X-IronPort-AV: E=Sophos;i="4.77,579,1336348800"; d="scan'208";a="13526342" Date: Fri, 13 Jul 2012 18:14:33 +0100 From: Stefano Stabellini X-X-Sender: sstabellini@kaball.uk.xensource.com To: Konrad Rzeszutek Wilk CC: Stefano Stabellini , "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 In-Reply-To: <20120709144005.GA12102@phenom.dumpdata.com> Message-ID: 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> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. > > 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/ >