From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1762787AbYGaAOw (ORCPT ); Wed, 30 Jul 2008 20:14:52 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756046AbYGaANu (ORCPT ); Wed, 30 Jul 2008 20:13:50 -0400 Received: from mx1.suse.de ([195.135.220.2]:38776 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762124AbYGaANs (ORCPT ); Wed, 30 Jul 2008 20:13:48 -0400 Date: Wed, 30 Jul 2008 16:58:48 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org, jejb@kernel.org Cc: Justin Forbes , Zwane Mwaikambo , "Theodore Ts'o" , Randy Dunlap , Dave Jones , Chuck Wolber , Chris Wedgwood , Michael Krufky , Chuck Ebbert , Domenico Andreoli , Willy Tarreau , Rodrigo Rubira Branco , Jake Edge , Eugene Teo , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, David Brownell , Andrew Victor Subject: [patch 27/62] rtc-at91rm9200: avoid spurious irqs Message-ID: <20080730235848.GA12896@suse.de> References: <20080730233050.332789722@mini.kroah.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline; filename="rtc-at91rm9200-avoid-spurious-irqs.patch" In-Reply-To: <20080730234915.GA12426@suse.de> User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.26 -stable review patch. If anyone has any objections, please let us know. ------------------ From: David Brownell commit 449321b39f6c6ebfa15d6da24f134240bd51db29 upstream This fixes kernel http://bugzilla.kernel.org/show_bug.cgi?id=11112 (bogus RTC update IRQs reported) for rtc-at91rm9200 by scrubbing old IRQ status before enabling IRQs. It also removes nonfunctional periodic IRQ support from this driver; only update IRQs are reported, or provided by the hardware. I suspect some other RTCs probably have versions of #11112; it's easy to overlook, since most non-RTC drivers don't care about spurious IRQs: they're not reported to userspace. Signed-off-by: David Brownell Report-by: W Unruh Cc: Andrew Victor Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- drivers/rtc/rtc-at91rm9200.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) --- a/drivers/rtc/rtc-at91rm9200.c +++ b/drivers/rtc/rtc-at91rm9200.c @@ -175,8 +175,10 @@ static int at91_rtc_setalarm(struct devi | BIN2BCD(tm.tm_mday) << 24 | AT91_RTC_DATEEN | AT91_RTC_MTHEN); - if (alrm->enabled) + if (alrm->enabled) { + at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM); at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM); + } pr_debug("%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__, at91_alarm_year, tm.tm_mon, tm.tm_mday, tm.tm_hour, @@ -195,28 +197,22 @@ static int at91_rtc_ioctl(struct device pr_debug("%s(): cmd=%08x, arg=%08lx.\n", __func__, cmd, arg); + /* important: scrub old status before enabling IRQs */ switch (cmd) { case RTC_AIE_OFF: /* alarm off */ at91_sys_write(AT91_RTC_IDR, AT91_RTC_ALARM); break; case RTC_AIE_ON: /* alarm on */ + at91_sys_write(AT91_RTC_SCCR, AT91_RTC_ALARM); at91_sys_write(AT91_RTC_IER, AT91_RTC_ALARM); break; case RTC_UIE_OFF: /* update off */ - case RTC_PIE_OFF: /* periodic off */ at91_sys_write(AT91_RTC_IDR, AT91_RTC_SECEV); break; case RTC_UIE_ON: /* update on */ - case RTC_PIE_ON: /* periodic on */ + at91_sys_write(AT91_RTC_SCCR, AT91_RTC_SECEV); at91_sys_write(AT91_RTC_IER, AT91_RTC_SECEV); break; - case RTC_IRQP_READ: /* read periodic alarm frequency */ - ret = put_user(AT91_RTC_FREQ, (unsigned long *) arg); - break; - case RTC_IRQP_SET: /* set periodic alarm frequency */ - if (arg != AT91_RTC_FREQ) - ret = -EINVAL; - break; default: ret = -ENOIOCTLCMD; break; --