On Sat, 12 Mar 2005, Venkatesh Pallipadi wrote:
> On Sat, Mar 12, 2005 at 09:25:13AM -0700, Zwane Mwaikambo wrote:
> > On Sat, 12 Mar 2005, George Anzinger wrote:
> >
> > > And more... That this occures implies we are attempting to update the cmos
> > > clock on resume seems wrong. One would presume that the time is wrong at
> > > this
> > > time and we are about to save that wrong time. Possibly the APM code
> > > should
> > > change time_status to STA_UNSYNC on the way into the sleep (or what ever
> > > it is
> > > called). Who should we ping with this?
> >
> > timer_resume, which appears to be the problem, wants to calculate amount
> > of time was spent suspended, also your unconditional irq enable in
> > get_cmos_time breaks the atomicity of device_power_up and would deadlock
> > in sections of code which call get_time_diff() with xtime_lock held. I
> > sent a patch subject "APM: fix interrupts enabled in device_power_up"
> > which should address this.
> >
>
> How about this patch? Also fixes one other use of rtc_lock in
> acpi/sleep/proc.c
>
> rtc_lock is held during timer interrupts. So, we should block interrupts
> while holding it.
It's certainly a lot safer with saving/restoring eflags and the
drivers/acpi/sleep/proc.c change is a good catch, but i think the
get_cmos_time() callers should take care of the interrupt disabling. btw,
s/spin_unlock_restore/spin_unlock_irqrestore/. Please submit the proc.c
change.
Thanks,
Zwane
> Signed-off-by: Venkatesh Pallipadi <[EMAIL PROTECTED]>
>
> --- linux-2.6.10/arch/i386/kernel/time.c.org 2005-03-12 10:38:23.000000000
> -0800
> +++ linux-2.6.10/arch/i386/kernel/time.c 2005-03-12 10:40:26.000000000
> -0800
> @@ -305,15 +305,16 @@ irqreturn_t timer_interrupt(int irq, voi
> unsigned long get_cmos_time(void)
> {
> unsigned long retval;
> + unsigned long flags;
>
> - spin_lock(&rtc_lock);
> + spin_lock_irqsave(&rtc_lock, flags);
>
> if (efi_enabled)
> retval = efi_get_time();
> else
> retval = mach_get_cmos_time();
>
> - spin_unlock(&rtc_lock);
> + spin_unlock_restore(&rtc_lock, flags);
>
> return retval;
> }
> --- linux-2.6.10/drivers/acpi/sleep/proc.c.org 2005-03-12
> 10:50:40.000000000 -0800
> +++ linux-2.6.10/drivers/acpi/sleep/proc.c 2005-03-12 10:53:08.000000000
> -0800
> @@ -84,10 +84,11 @@ static int acpi_system_alarm_seq_show(st
> u32 sec, min, hr;
> u32 day, mo, yr;
> unsigned char rtc_control = 0;
> + unsigned long flags;
>
> ACPI_FUNCTION_TRACE("acpi_system_alarm_seq_show");
>
> - spin_lock(&rtc_lock);
> + spin_lock_irqsave(&rtc_lock, flags);
>
> sec = CMOS_READ(RTC_SECONDS_ALARM);
> min = CMOS_READ(RTC_MINUTES_ALARM);
> @@ -109,7 +110,7 @@ static int acpi_system_alarm_seq_show(st
> else
> yr = CMOS_READ(RTC_YEAR);
>
> - spin_unlock(&rtc_lock);
> + spin_unlock_restore(&rtc_lock, flags);
>
> if (!(rtc_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) {
> BCD_TO_BIN(sec);
>
-
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