linux-kernel - Re: [PATCH 08/12] rtc: omap: restore irq state after reading TC registers

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Date:	Fri, 10 Oct 2014 13:02:31 -0500
From:	Felipe Balbi <balbi@...com>
To:	Johan Hovold <johan@...nel.org>
CC:	Alessandro Zummo <a.zummo@...ertech.it>,
	Tony Lindgren <tony@...mide.com>,
	Benoît Cousson <bcousson@...libre.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Felipe Balbi <balbi@...com>, Lokesh Vutla <lokeshvutla@...com>,
	Guenter Roeck <linux@...ck-us.net>,
	Colin Foe-Parker <colin.foeparker@...icpd.com>,
	<nsekhar@...com>, <t-kristo@...com>, <j-keerthy@...com>,
	<linux-omap@...r.kernel.org>,
	<linux-arm-kernel@...ts.infradead.org>,
	<devicetree@...r.kernel.org>, <rtc-linux@...glegroups.com>,
	<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 08/12] rtc: omap: restore irq state after reading TC
 registers

Hi,

On Thu, Oct 09, 2014 at 09:06:30PM +0200, Johan Hovold wrote:
> Make sure to restore local irq state when reading the timer/calendar
> (TC) registers, so that omap_rtc_read_time() can be called with
> interrupts disabled.
> 
> Signed-off-by: Johan Hovold <johan@...nel.org>
> ---
>  drivers/rtc/rtc-omap.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-omap.c b/drivers/rtc/rtc-omap.c
> index 0ef016553a97..62e2e9a9887a 100644
> --- a/drivers/rtc/rtc-omap.c
> +++ b/drivers/rtc/rtc-omap.c
> @@ -239,8 +239,10 @@ static void bcd2tm(struct rtc_time *tm)
>  
>  static int omap_rtc_read_time(struct device *dev, struct rtc_time *tm)
>  {
> +	unsigned long flags;
> +
>  	/* we don't report wday/yday/isdst ... */
> -	local_irq_disable();
> +	local_irq_save(flags);

you should really convert these to a real spin_lock_irq*(), that's
because local_irq* do not get re-written with RT patchset, so this
pretty much "breaks" RT.

-- 
balbi

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