On Sat, Mar 12, 2005 at 08:21:29AM -0700, Zwane Mwaikambo wrote:
> On Sat, 12 Mar 2005, J. Bruce Fields wrote:
>
> > On APM resume this morning on my Thinkpad X31, I got a "spin_lock is
> > already locked" error; see below. This doesn't happen on every resume,
> > though it's happened before. The kernel is 2.6.11 plus a bunch of
> > (hopefully unrelated...) NFS patches.
> >
> > Mar 12 07:07:31 puzzle kernel: PCI: Setting latency timer of device
> > 0000:00:1f.5 to 64
> > Mar 12 07:07:31 puzzle kernel: arch/i386/kernel/time.c:179:
> > spin_lock(arch/i386/kernel/time.c:c0603c28) already locked by
> > arch/i386/kernel/time.c/309
> > Mar 12 07:07:31 puzzle kernel: arch/i386/kernel/time.c:316:
> > spin_unlock(arch/i386/kernel/time.c:c0603c28) not locked
>
> APM was calling device_power_down and device_power_up with interrupts
> enabled, resulting in a few calls to get_cmos_time being done with
> interrupts enabled (rtc_lock needs to be acquired with interrupts
> disabled).
Thanks, I haven't been following the discussion carefully, but for
what's it worth I did apply that patch and now (a few suspend-resume
cycles later) haven't seen the spin_lock warning or seen any other ill
effects.
Let me know if there's any testing it would be useful for me to do.
--Bruce Fields
> Signed-off-by: Zwane Mwaikambo <[EMAIL PROTECTED]>
>
> ===== arch/i386/kernel/apm.c 1.72 vs edited =====
> --- 1.72/arch/i386/kernel/apm.c 2005-01-20 22:02:11 -07:00
> +++ edited/arch/i386/kernel/apm.c 2005-03-12 08:17:52 -07:00
> @@ -1202,10 +1202,11 @@
> }
>
> device_suspend(PMSG_SUSPEND);
> + local_irq_disable();
> device_power_down(PMSG_SUSPEND);
>
> /* serialize with the timer interrupt */
> - write_seqlock_irq(&xtime_lock);
> + write_seqlock(&xtime_lock);
>
> /* protect against access to timer chip registers */
> spin_lock(&i8253_lock);
> @@ -1216,20 +1217,22 @@
> * We'll undo any timer changes due to interrupts below.
> */
> spin_unlock(&i8253_lock);
> - write_sequnlock_irq(&xtime_lock);
> + write_sequnlock(&xtime_lock);
> + local_irq_enable();
>
> save_processor_state();
> err = set_system_power_state(APM_STATE_SUSPEND);
> restore_processor_state();
>
> - write_seqlock_irq(&xtime_lock);
> + local_irq_disable();
> + write_seqlock(&xtime_lock);
> spin_lock(&i8253_lock);
> reinit_timer();
> set_time();
> ignore_normal_resume = 1;
>
> spin_unlock(&i8253_lock);
> - write_sequnlock_irq(&xtime_lock);
> + write_sequnlock(&xtime_lock);
>
> if (err == APM_NO_ERROR)
> err = APM_SUCCESS;
> @@ -1237,6 +1240,7 @@
> apm_error("suspend", err);
> err = (err == APM_SUCCESS) ? 0 : -EIO;
> device_power_up();
> + local_irq_enable();
> device_resume();
> pm_send_all(PM_RESUME, (void *)0);
> queue_event(APM_NORMAL_RESUME, NULL);
> @@ -1255,17 +1259,22 @@
> {
> int err;
>
> + local_irq_disable();
> device_power_down(PMSG_SUSPEND);
> /* serialize with the timer interrupt */
> - write_seqlock_irq(&xtime_lock);
> + write_seqlock(&xtime_lock);
> /* If needed, notify drivers here */
> get_time_diff();
> - write_sequnlock_irq(&xtime_lock);
> + write_sequnlock(&xtime_lock);
> + local_irq_enable();
>
> err = set_system_power_state(APM_STATE_STANDBY);
> if ((err != APM_SUCCESS) && (err != APM_NO_ERROR))
> apm_error("standby", err);
> +
> + local_irq_disable();
> device_power_up();
> + local_irq_enable();
> }
>
> static apm_event_t get_event(void)
-
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