From: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
To: alessandro.zummo@towertech.it
Cc: akpm@linux-foundation.org, rtc-linux@googlegroups.com,
linux-kernel@vger.kernel.org, hcegtvedt@atmel.com,
vapier@gentoo.org, rongkai.zhan@windriver.com,
balajirrao@openmoko.org, david-b@pacbell.net,
broonie@opensource.wolfsonmicro.com
Subject: Re: [PATCH] rtc: Make rtc_update_irq callable with irqs enabled
Date: Thu, 23 Apr 2009 23:51:41 +0900 (JST) [thread overview]
Message-ID: <20090423.235141.61509229.anemo@mba.ocn.ne.jp> (raw)
In-Reply-To: <20090410005820.4fcfcc1f@i1501.lan.towertech.it>
[Add CCs to authers or original committers of each mentioned driver]
On Fri, 10 Apr 2009 00:58:20 +0200, Alessandro Zummo <alessandro.zummo@towertech.it> wrote:
> On Thu, 9 Apr 2009 15:39:21 -0700
> Andrew Morton <akpm@linux-foundation.org> wrote:
>
> > > The rtc_update_irq() might be called with irqs enabled, if a interrupt
> > > handler was registered without IRQF_DISABLED.
> >
> > Why? What are the consequences of not merging the patch? Is it a
> > bugfix? If so, what are the user-visible effects of the bug?
>
> rtc_update_irq() is called by a driver, and a driver
> is supposed to know when it's doing the call.
>
> The driver can either use IRQF_DISABLED or disable the
> interrupts in some other ways.
>
> I also suspect this is some legacy we are carrying on,
> so it's better to leave the decision on the interrupt
> handling to the driver itself.
>
> Unless I'm missing something.
Then here is list of (potentialy) broken rtc drivers:
rtc-at32ap700x.c
rtc-bfin.c
rtc-m48t59.c
rtc-pcf50633.c
rtc-twl4030.c
rtc-wm8350.c
I'm not sure there are any real problem on these drivers. It seems
IRQF_DISABLED would be suitable for at32ap700x, bfin and m48t59, and
local_irq_disable would be suitable for others.
The IRQF_DISABLED fixes would be better regardless of the
rtc_update_irq() API change. And local_irq_disable fixes are not
needed (and should be reverted) if the API change was acked, but no
harm for short term fix.
Note that just adding IRQF_DISABLED will cause "IRQF_DISABLED is not
guaranteed on shared IRQs" warning. So you should consider of
removing IRQF_SHARED, or finding other way.
---
Atsushi Nemoto
next prev parent reply other threads:[~2009-04-23 14:51 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-04-06 16:50 [PATCH] rtc: Make rtc_update_irq callable with irqs enabled Atsushi Nemoto
2009-04-09 22:39 ` Andrew Morton
2009-04-09 22:58 ` Alessandro Zummo
2009-04-23 14:51 ` Atsushi Nemoto [this message]
2009-04-23 15:02 ` Alessandro Zummo
2009-04-23 15:07 ` [rtc-linux] " Mike Frysinger
[not found] ` <200904091627.15776.david-b@pacbell.net>
2009-04-23 15:29 ` Atsushi Nemoto
2009-04-23 15:46 ` Alessandro Zummo
2009-04-23 18:15 ` David Brownell
2009-04-23 18:27 ` [rtc-linux] " Alessandro Zummo
2009-04-23 19:02 ` David Brownell
2009-04-23 19:09 ` Alessandro Zummo
2009-04-23 19:25 ` David Brownell
2009-04-23 19:26 ` Alessandro Zummo
2009-04-23 19:45 ` David Brownell
2009-04-23 19:55 ` Alessandro Zummo
2009-04-24 9:31 ` David Brownell
2009-04-24 10:01 ` Alessandro Zummo
2009-04-24 11:10 ` David Brownell
2009-04-24 11:13 ` Alessandro Zummo
2009-04-24 16:48 ` Atsushi Nemoto
2009-04-24 17:06 ` Atsushi Nemoto
2009-04-24 19:41 ` Alessandro Zummo
2009-04-25 12:40 ` Atsushi Nemoto
2009-04-28 13:13 ` Hans-Christian Egtvedt
2009-04-28 15:56 ` Atsushi Nemoto
2009-04-23 15:37 ` Alessandro Zummo
2009-04-23 16:30 ` Mike Frysinger
2009-04-23 16:40 ` Alessandro Zummo
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