From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756002AbYIIAzk (ORCPT ); Mon, 8 Sep 2008 20:55:40 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754852AbYIIAzc (ORCPT ); Mon, 8 Sep 2008 20:55:32 -0400 Received: from smtp122.sbc.mail.sp1.yahoo.com ([69.147.64.95]:23270 "HELO smtp122.sbc.mail.sp1.yahoo.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754751AbYIIAzb (ORCPT ); Mon, 8 Sep 2008 20:55:31 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=s1024; d=pacbell.net; h=Received:X-YMail-OSG:X-Yahoo-Newman-Property:From:To:Subject:Date:User-Agent:Cc:References:In-Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding:Content-Disposition:Message-Id; b=MPEI7bBUzRvyNs3LUSfIUDPWu+OCXuG+k/o37ljqUkJVmsD4EanKxYdk3qUfR8NLfV4sOEA3DkN5WGd/PdjBZ5PgXKDigrBorWPmwJ8ef4QYSfwAowiTP3RTomGv/Cq+kbva73BfXJ+AE8G+aGmwD9WPEPDHo4RENRO/WEvMavo= ; X-YMail-OSG: NTTRycoVM1lX_kKpFob9qQb_zL2elcil2k4Yz7jBkL__DgWIzX9di2lYAr3lfdZ57G8.v5XRJnmnWZboEElJZ.KPSjsW5DiW0gceBCIDz5smCYdMAyTgYSatHMhd04Y- X-Yahoo-Newman-Property: ymail-3 From: David Brownell To: David Miller Subject: Re: [PATCH] fix RTC_CLASS regression with PARISC Date: Mon, 8 Sep 2008 17:55:25 -0700 User-Agent: KMail/1.9.9 Cc: James.Bottomley@hansenpartnership.com, torvalds@linux-foundation.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-parisc@vger.kernel.org, alessandro.zummo@towertech.it References: <1220914847.8074.81.camel@localhost.localdomain> <200809081629.21125.david-b@pacbell.net> <20080908.164427.216880550.davem@davemloft.net> In-Reply-To: <20080908.164427.216880550.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200809081755.26148.david-b@pacbell.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Monday 08 September 2008, David Miller wrote: > From: David Brownell > Date: Mon, 8 Sep 2008 16:29:20 -0700 > > > That said, there's a bit of unresolved stuff around NTP hooks > > in the kernel. Some patches are pending to let thtem work with > > the RTC framework -- where writing an RTC may need to sleep, > > for example because the RTC is on an I2C or SPI bus. And > > then there's the discussion of whether that shouldn't all be > > handled by NTPD anyway, no special kernel support desired. > > Alessandro has opinions there. ;) > > My update_persistent_clock() on sparc64 is: > > int update_persistent_clock(struct timespec now) > { > struct rtc_device *rtc = rtc_class_open("rtc0"); I'd be tempted to cache that ... notice how you never close it, too. That will goof lots of refcounts... > if (rtc) > return rtc_set_mmss(rtc, now.tv_sec); > > return -1; > } > > and that should handle this NTP shouldn't it? Depends on what patches have applied; I've lost track of whether it's now ok for update_persistent_clock() to sleep. Previously it was not, without a critical patch (appended). Having something like that work is *certainly* a goal, at least for those who don't want to get rid of those kernel NTP hooks entirely. And of course, once that works I'd claim it should live in drivers/rtc for the benefit of other platforms. :) - Dave =============== CUT ON THE DOTTED LINE ================== Subject: ntp: let update_persistent_clock() sleep From: "Maciej W. Rozycki" This is a change that makes the 11-minute RTC update be run in the process context. This is so that update_persistent_clock() can sleep, which may be required for certain types of RTC hardware -- most notably I2C devices. Signed-off-by: Maciej W. Rozycki Cc: Thomas Gleixner Cc: Roman Zippel Cc: Rik van Riel Cc: Alessandro Zummo Cc: David Brownell Signed-off-by: Andrew Morton --- kernel/time/ntp.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) --- a/kernel/time/ntp.c 2008-06-30 21:20:51.000000000 -0700 +++ b/kernel/time/ntp.c 2008-06-30 21:21:27.000000000 -0700 @@ -10,13 +10,13 @@ #include #include -#include #include #include #include #include #include #include +#include #include /* @@ -218,11 +218,11 @@ void second_overflow(void) /* Disable the cmos update - used by virtualization and embedded */ int no_sync_cmos_clock __read_mostly; -static void sync_cmos_clock(unsigned long dummy); +static void sync_cmos_clock(struct work_struct *work); -static DEFINE_TIMER(sync_cmos_timer, sync_cmos_clock, 0, 0); +static DECLARE_DELAYED_WORK(sync_cmos_work, sync_cmos_clock); -static void sync_cmos_clock(unsigned long dummy) +static void sync_cmos_clock(struct work_struct *work) { struct timespec now, next; int fail = 1; @@ -258,13 +258,13 @@ static void sync_cmos_clock(unsigned lon next.tv_sec++; next.tv_nsec -= NSEC_PER_SEC; } - mod_timer(&sync_cmos_timer, jiffies + timespec_to_jiffies(&next)); + schedule_delayed_work(&sync_cmos_work, timespec_to_jiffies(&next)); } static void notify_cmos_timer(void) { if (!no_sync_cmos_clock) - mod_timer(&sync_cmos_timer, jiffies + 1); + schedule_delayed_work(&sync_cmos_work, 0); } #else