* RTC , ds1307 I2C driver and NTP does not work.
@ 2006-11-17 16:38 Joakim Tjernlund
2006-11-17 16:57 ` Kumar Gala
0 siblings, 1 reply; 7+ messages in thread
From: Joakim Tjernlund @ 2006-11-17 16:38 UTC (permalink / raw
To: linuxppc-dev
I get this when I activate NTP and ntp "sync" the time the I2C HW clock.
BUG: scheduling while atomic: swapper/0x00010000/0
Call Trace:^M
[C0245C80] [C000860C] show_stack+0x48/0x194 (unreliable)
[C0245CB0] [C01BEFF4] schedule+0x5d4/0x618
[C0245CF0] [C01BF9C8] schedule_timeout+0x70/0xd0
[C0245D30] [C014416C] i2c_wait+0x164/0x1d8
[C0245D80] [C0144490] mpc_xfer+0x2b0/0x3a8
[C0245DD0] [C01423E8] i2c_transfer+0x58/0x7c
[C0245DF0] [C0141124] ds1307_set_time+0x1bc/0x234
[C0245E00] [C013F82C] rtc_set_time+0xb0/0xb8^M
[C0245E20] [C000BFC4] set_rtc_class_time+0x34/0x58
[C0245E40] [C000C8D0] timer_interrupt+0x5a0/0x5fc
[C0245EE0] [C000F7B0] ret_from_except+0x0/0x14
--- Exception: 901 at cpu_idle+0xc8/0xf0
LR = cpu_idle+0xec/0xf0
[C0245FC0] [C000388C] rest_init+0x28/0x38
[C0245FD0] [C01F36E0] start_kernel+0x1d8/0x228
[C0245FF0] [00003438] 0x3438
I have activated RTC CLASS and have this in my board file:
#ifdef CONFIG_RTC_CLASS
late_initcall(rtc_class_hookup);
#endif
kernel 2.6.19-rc5
Jocke
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RTC , ds1307 I2C driver and NTP does not work.
2006-11-17 16:38 RTC , ds1307 I2C driver and NTP does not work Joakim Tjernlund
@ 2006-11-17 16:57 ` Kumar Gala
2006-11-17 17:44 ` Scott Wood
2006-11-18 0:54 ` Luong Ngo
0 siblings, 2 replies; 7+ messages in thread
From: Kumar Gala @ 2006-11-17 16:57 UTC (permalink / raw
To: joakim.tjernlund; +Cc: linuxppc-dev
On Nov 17, 2006, at 10:38 AM, Joakim Tjernlund wrote:
> I get this when I activathte NTP and ntp "sync" the time the I2C HW
> clock.
You may be better off posting this to lkml and copy the i2c list (and
rtc if one exists). Since its more a driver issue than anything
really ppc specific. Clearly we are doing schedules() in mpc_xfer()
and maybe we shouldn't be.
- kumar
> BUG: scheduling while atomic: swapper/0x00010000/0
> Call Trace:^M
> [C0245C80] [C000860C] show_stack+0x48/0x194 (unreliable)
> [C0245CB0] [C01BEFF4] schedule+0x5d4/0x618
> [C0245CF0] [C01BF9C8] schedule_timeout+0x70/0xd0
> [C0245D30] [C014416C] i2c_wait+0x164/0x1d8
> [C0245D80] [C0144490] mpc_xfer+0x2b0/0x3a8
> [C0245DD0] [C01423E8] i2c_transfer+0x58/0x7c
> [C0245DF0] [C0141124] ds1307_set_time+0x1bc/0x234
> [C0245E00] [C013F82C] rtc_set_time+0xb0/0xb8^M
> [C0245E20] [C000BFC4] set_rtc_class_time+0x34/0x58
> [C0245E40] [C000C8D0] timer_interrupt+0x5a0/0x5fc
> [C0245EE0] [C000F7B0] ret_from_except+0x0/0x14
> --- Exception: 901 at cpu_idle+0xc8/0xf0
> LR = cpu_idle+0xec/0xf0
> [C0245FC0] [C000388C] rest_init+0x28/0x38
> [C0245FD0] [C01F36E0] start_kernel+0x1d8/0x228
> [C0245FF0] [00003438] 0x3438
>
> I have activated RTC CLASS and have this in my board file:
> #ifdef CONFIG_RTC_CLASS
> late_initcall(rtc_class_hookup);
> #endif
>
> kernel 2.6.19-rc5
>
> Jocke
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RTC , ds1307 I2C driver and NTP does not work.
2006-11-17 16:57 ` Kumar Gala
@ 2006-11-17 17:44 ` Scott Wood
2006-11-18 0:54 ` Luong Ngo
1 sibling, 0 replies; 7+ messages in thread
From: Scott Wood @ 2006-11-17 17:44 UTC (permalink / raw
To: Kumar Gala; +Cc: linuxppc-dev
Kumar Gala wrote:
> On Nov 17, 2006, at 10:38 AM, Joakim Tjernlund wrote:
>
>
>>I get this when I activathte NTP and ntp "sync" the time the I2C HW
>>clock.
>
>
> You may be better off posting this to lkml and copy the i2c list (and
> rtc if one exists). Since its more a driver issue than anything
> really ppc specific. Clearly we are doing schedules() in mpc_xfer()
> and maybe we shouldn't be.
It's interrupt unsafe before that; rtc_set_time calls
mutex_lock_interruptible. If the RTC must be set from an interrupt, it
should be via a workqueue.
-Scott
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RTC , ds1307 I2C driver and NTP does not work.
2006-11-17 16:57 ` Kumar Gala
2006-11-17 17:44 ` Scott Wood
@ 2006-11-18 0:54 ` Luong Ngo
1 sibling, 0 replies; 7+ messages in thread
From: Luong Ngo @ 2006-11-18 0:54 UTC (permalink / raw
To: Kumar Gala; +Cc: linuxppc-dev
[-- Attachment #1: Type: text/plain, Size: 2346 bytes --]
Joakim,
We are having the exact same problem. And if I understand correctly, the
schedule call in i2c-mpc driver is because we are waiting for the interrupt
signaling a byte transfer complete. If the interrupt does not yet come, the
driver call schedule to wait, both for polling mode and interrupt mode. I
am not sure if it is some problem occurs making the interrupt not coming
quick enough. We still try to resolve. Please let us know if you find a
solution and we definitely will post our finding if we can resolve.
-Ngo
On 11/17/06, Kumar Gala <galak@kernel.crashing.org> wrote:
>
>
> On Nov 17, 2006, at 10:38 AM, Joakim Tjernlund wrote:
>
> > I get this when I activathte NTP and ntp "sync" the time the I2C HW
> > clock.
>
> You may be better off posting this to lkml and copy the i2c list (and
> rtc if one exists). Since its more a driver issue than anything
> really ppc specific. Clearly we are doing schedules() in mpc_xfer()
> and maybe we shouldn't be.
>
> - kumar
>
> > BUG: scheduling while atomic: swapper/0x00010000/0
> > Call Trace:^M
> > [C0245C80] [C000860C] show_stack+0x48/0x194 (unreliable)
> > [C0245CB0] [C01BEFF4] schedule+0x5d4/0x618
> > [C0245CF0] [C01BF9C8] schedule_timeout+0x70/0xd0
> > [C0245D30] [C014416C] i2c_wait+0x164/0x1d8
> > [C0245D80] [C0144490] mpc_xfer+0x2b0/0x3a8
> > [C0245DD0] [C01423E8] i2c_transfer+0x58/0x7c
> > [C0245DF0] [C0141124] ds1307_set_time+0x1bc/0x234
> > [C0245E00] [C013F82C] rtc_set_time+0xb0/0xb8^M
> > [C0245E20] [C000BFC4] set_rtc_class_time+0x34/0x58
> > [C0245E40] [C000C8D0] timer_interrupt+0x5a0/0x5fc
> > [C0245EE0] [C000F7B0] ret_from_except+0x0/0x14
> > --- Exception: 901 at cpu_idle+0xc8/0xf0
> > LR = cpu_idle+0xec/0xf0
> > [C0245FC0] [C000388C] rest_init+0x28/0x38
> > [C0245FD0] [C01F36E0] start_kernel+0x1d8/0x228
> > [C0245FF0] [00003438] 0x3438
> >
> > I have activated RTC CLASS and have this in my board file:
> > #ifdef CONFIG_RTC_CLASS
> > late_initcall(rtc_class_hookup);
> > #endif
> >
> > kernel 2.6.19-rc5
> >
> > Jocke
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > Linuxppc-dev@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
[-- Attachment #2: Type: text/html, Size: 3082 bytes --]
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RTC , ds1307 I2C driver and NTP does not work.
2006-11-17 17:38 FW: " Joakim Tjernlund
@ 2006-11-18 14:19 ` Jean Delvare
2006-11-18 14:51 ` Joakim Tjernlund
0 siblings, 1 reply; 7+ messages in thread
From: Jean Delvare @ 2006-11-18 14:19 UTC (permalink / raw
To: Joakim Tjernlund, Kumar Gala; +Cc: LKML, i2c
On Fri, 17 Nov 2006 18:38:10 +0100, Joakim Tjernlund wrote:
> On Nov 17, 2006, at 10:38 AM, Joakim Tjernlund wrote:
>
> > I get this when I activathte NTP and ntp "sync" the time the I2C HW
> > clock.
>
> You may be better off posting this to lkml and copy the i2c list (and
> rtc if one exists). Since its more a driver issue than anything
> really ppc specific. Clearly we are doing schedules() in mpc_xfer()
> and maybe we shouldn't be.
It's OK to schedule or sleep in mpc_xfer. It's not OK to call mpc_xfer
from an interrupt context, which is what appears to be happening here.
So the ds1307 driver would need to be changed not to directly call
i2c_transfer from the interrupt. Using a workqueue should work.
That being said, I wonder why one would want to set the time from an
interrupt context in the first place. Maybe that's what needs fixing.
> > BUG: scheduling while atomic: swapper/0x00010000/0
> > Call Trace:^M
> > [C0245C80] [C000860C] show_stack+0x48/0x194 (unreliable)
> > [C0245CB0] [C01BEFF4] schedule+0x5d4/0x618
> > [C0245CF0] [C01BF9C8] schedule_timeout+0x70/0xd0
> > [C0245D30] [C014416C] i2c_wait+0x164/0x1d8
> > [C0245D80] [C0144490] mpc_xfer+0x2b0/0x3a8
> > [C0245DD0] [C01423E8] i2c_transfer+0x58/0x7c
> > [C0245DF0] [C0141124] ds1307_set_time+0x1bc/0x234
> > [C0245E00] [C013F82C] rtc_set_time+0xb0/0xb8^M
> > [C0245E20] [C000BFC4] set_rtc_class_time+0x34/0x58
> > [C0245E40] [C000C8D0] timer_interrupt+0x5a0/0x5fc
> > [C0245EE0] [C000F7B0] ret_from_except+0x0/0x14
> > --- Exception: 901 at cpu_idle+0xc8/0xf0
> > LR = cpu_idle+0xec/0xf0
> > [C0245FC0] [C000388C] rest_init+0x28/0x38
> > [C0245FD0] [C01F36E0] start_kernel+0x1d8/0x228
> > [C0245FF0] [00003438] 0x3438
> >
> > I have activated RTC CLASS and have this in my board file:
> > #ifdef CONFIG_RTC_CLASS
> > late_initcall(rtc_class_hookup);
> > #endif
> >
> > kernel 2.6.19-rc5
> >
> > Jocke
--
Jean Delvare
^ permalink raw reply [flat|nested] 7+ messages in thread
* RE: RTC , ds1307 I2C driver and NTP does not work.
2006-11-18 14:19 ` Jean Delvare
@ 2006-11-18 14:51 ` Joakim Tjernlund
2006-11-19 11:20 ` Jean Delvare
0 siblings, 1 reply; 7+ messages in thread
From: Joakim Tjernlund @ 2006-11-18 14:51 UTC (permalink / raw
To: 'Jean Delvare', 'Kumar Gala'; +Cc: 'LKML', i2c
>
> On Fri, 17 Nov 2006 18:38:10 +0100, Joakim Tjernlund wrote:
> > On Nov 17, 2006, at 10:38 AM, Joakim Tjernlund wrote:
> >
> > > I get this when I activathte NTP and ntp "sync" the time
> the I2C HW
> > > clock.
> >
> > You may be better off posting this to lkml and copy the i2c
> list (and
> > rtc if one exists). Since its more a driver issue than anything
> > really ppc specific. Clearly we are doing schedules() in
> mpc_xfer()
> > and maybe we shouldn't be.
>
> It's OK to schedule or sleep in mpc_xfer. It's not OK to call mpc_xfer
> from an interrupt context, which is what appears to be happening here.
> So the ds1307 driver would need to be changed not to directly call
> i2c_transfer from the interrupt. Using a workqueue should work.
>
> That being said, I wonder why one would want to set the time from an
> interrupt context in the first place. Maybe that's what needs fixing.
That's the way kernel NTP code always has done it. Probably to minimize latency, ideally
you want to set the time when a new second occur since that's what most RTC HW expects.
Will a workqueue run directly after the one return from IRQ context?
>
> > > BUG: scheduling while atomic: swapper/0x00010000/0
> > > Call Trace:^M
> > > [C0245C80] [C000860C] show_stack+0x48/0x194 (unreliable)
> > > [C0245CB0] [C01BEFF4] schedule+0x5d4/0x618
> > > [C0245CF0] [C01BF9C8] schedule_timeout+0x70/0xd0
> > > [C0245D30] [C014416C] i2c_wait+0x164/0x1d8
> > > [C0245D80] [C0144490] mpc_xfer+0x2b0/0x3a8
> > > [C0245DD0] [C01423E8] i2c_transfer+0x58/0x7c
> > > [C0245DF0] [C0141124] ds1307_set_time+0x1bc/0x234
> > > [C0245E00] [C013F82C] rtc_set_time+0xb0/0xb8^M
> > > [C0245E20] [C000BFC4] set_rtc_class_time+0x34/0x58
> > > [C0245E40] [C000C8D0] timer_interrupt+0x5a0/0x5fc
> > > [C0245EE0] [C000F7B0] ret_from_except+0x0/0x14
> > > --- Exception: 901 at cpu_idle+0xc8/0xf0
> > > LR = cpu_idle+0xec/0xf0
> > > [C0245FC0] [C000388C] rest_init+0x28/0x38
> > > [C0245FD0] [C01F36E0] start_kernel+0x1d8/0x228
> > > [C0245FF0] [00003438] 0x3438
> > >
> > > I have activated RTC CLASS and have this in my board file:
> > > #ifdef CONFIG_RTC_CLASS
> > > late_initcall(rtc_class_hookup);
> > > #endif
> > >
> > > kernel 2.6.19-rc5
> > >
> > > Jocke
>
> --
> Jean Delvare
>
>
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: RTC , ds1307 I2C driver and NTP does not work.
2006-11-18 14:51 ` Joakim Tjernlund
@ 2006-11-19 11:20 ` Jean Delvare
0 siblings, 0 replies; 7+ messages in thread
From: Jean Delvare @ 2006-11-19 11:20 UTC (permalink / raw
To: Joakim Tjernlund; +Cc: Kumar Gala, LKML, i2c
Hi Joakim,
On Sat, 18 Nov 2006 15:51:09 +0100, Joakim Tjernlund wrote:
> > It's OK to schedule or sleep in mpc_xfer. It's not OK to call mpc_xfer
> > from an interrupt context, which is what appears to be happening here.
> > So the ds1307 driver would need to be changed not to directly call
> > i2c_transfer from the interrupt. Using a workqueue should work.
> >
> > That being said, I wonder why one would want to set the time from an
> > interrupt context in the first place. Maybe that's what needs fixing.
>
> That's the way kernel NTP code always has done it. Probably to minimize
> latency, ideally you want to set the time when a new second occur since
> that's what most RTC HW expects.
>
> Will a workqueue run directly after the one return from IRQ context?
There is no guarantee as to when the workqueue will process the request
as far as I know. The actual delay probably depends on the value of HZ.
There is no way around the delay in the case of I2C RTC chips anyway
(at least not with the current implementation), as the underlying I2C
bus driver may sleep as part of the bus transaction, and the RTC chip
driver can virtually be attached to every bus.
Note that the transaction itself will take some time anyway, I2C can be
quite slow.
--
Jean Delvare
^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2006-11-19 11:21 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2006-11-17 16:38 RTC , ds1307 I2C driver and NTP does not work Joakim Tjernlund
2006-11-17 16:57 ` Kumar Gala
2006-11-17 17:44 ` Scott Wood
2006-11-18 0:54 ` Luong Ngo
-- strict thread matches above, loose matches on Subject: below --
2006-11-17 17:38 FW: " Joakim Tjernlund
2006-11-18 14:19 ` Jean Delvare
2006-11-18 14:51 ` Joakim Tjernlund
2006-11-19 11:20 ` Jean Delvare
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