linux-kernel - Re: [PATCH -v2] RTC: Add an alarm disable quirk

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Date:	Mon, 22 Jul 2013 14:00:42 -0700
From:	John Stultz <john.stultz@...aro.org>
To:	Borislav Petkov <bp@...en8.de>
CC:	LKML <linux-kernel@...r.kernel.org>, Jiri Kosina <jkosina@...e.cz>,
	Borislav Petkov <bp@...e.de>,
	Thomas Gleixner <tglx@...utronix.de>,
	Rabin Vincent <rabin.vincent@...ricsson.com>
Subject: Re: [PATCH -v2] RTC: Add an alarm disable quirk

On 07/20/2013 10:00 AM, Borislav Petkov wrote:
> 41c7f7424259f ("rtc: Disable the alarm in the hardware (v2)") added the
> functionality to disable the RTC wake alarm when shutting down the box.
>
> However, there are at least two b0rked BIOSes we know about:
>
> https://bugzilla.novell.com/show_bug.cgi?id=812592
> https://bugzilla.novell.com/show_bug.cgi?id=805740
>
> where, when wakeup alarm is enabled in the BIOS, the machine reboots
> automatically right after shutdown, regardless of what wakeup time is
> programmed.

Also, just to clarify, on the affected machines, with this patch, 
wake-up alarm's will in effect be disabled, right?


> Bisecting the issue lead to this patch so disable its functionality with
> a DMI quirk only for those boxes.
>
> Signed-off-by: Borislav Petkov <bp@...e.de>
> Cc: Thomas Gleixner <tglx@...utronix.de>
> Cc: John Stultz <john.stultz@...aro.org>
> Cc: Rabin Vincent <rabin.vincent@...ricsson.com>
> ---
>   drivers/rtc/rtc-cmos.c | 40 +++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 39 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c
> index be06d7150de5..906b45c644e1 100644
> --- a/drivers/rtc/rtc-cmos.c
> +++ b/drivers/rtc/rtc-cmos.c
> @@ -34,11 +34,11 @@
>   #include <linux/interrupt.h>
>   #include <linux/spinlock.h>
>   #include <linux/platform_device.h>
> -#include <linux/mod_devicetable.h>
>   #include <linux/log2.h>
>   #include <linux/pm.h>
>   #include <linux/of.h>
>   #include <linux/of_platform.h>
> +#include <linux/dmi.h>
>   
>   /* this is for "generic access to PC-style RTC" using CMOS_READ/CMOS_WRITE */
>   #include <asm-generic/rtc.h>
> @@ -377,6 +377,39 @@ static int cmos_set_alarm(struct device *dev, struct rtc_wkalrm *t)
>   	return 0;
>   }
>   
> +/*
> + * Do not disable RTC alarm on shutdown - workaround for b0rked BIOSes.
> + */
> +static bool disable_alarm = true;
> +
> +static int __init clear_disable_alarm(const struct dmi_system_id *id)
> +{
> +	disable_alarm = false;
> +	return 0;
> +}
> +
> +static const struct dmi_system_id rtc_quirks[] __initconst = {
> +	/* https://bugzilla.novell.com/show_bug.cgi?id=805740 */
> +	{
> +		.callback = clear_disable_alarm,
> +		.ident    = "IBM Truman",
> +		.matches  = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "TOSHIBA"),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "4852570"),
> +		},
> +	},
> +	/* https://bugzilla.novell.com/show_bug.cgi?id=812592 */
> +	{
> +		.callback = clear_disable_alarm,
> +		.ident    = "Gigabyte GA-990XA-UD3",
> +		.matches  = {
> +			DMI_MATCH(DMI_SYS_VENDOR, "Gigabyte Technology Co., Ltd."),
> +			DMI_MATCH(DMI_PRODUCT_NAME, "GA-990XA-UD3"),
> +		},
> +	},
> +	{}
> +};
> +
>   static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
>   {
>   	struct cmos_rtc	*cmos = dev_get_drvdata(dev);
> @@ -385,6 +418,9 @@ static int cmos_alarm_irq_enable(struct device *dev, unsigned int enabled)
>   	if (!is_valid_irq(cmos->irq))
>   		return -EINVAL;
>   
> +	if (!disable_alarm)
> +		return 0;
> +

Did you want this in cmos_alarm_irq_enable? Or cmos_irq_disable?

thanks
-john

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