2008-01-16 03:32:25

by Yinghai Lu

[permalink] [raw]
Subject: hpet_late_init hang

"
commit e5ed385fa0d6f35406e3e3ed75e5eb9adeb811df
Author: Balaji Rao <[email protected]>
Date: Tue Jan 15 16:53:29 2008 +0100

Assign IRQs to HPET Timers
"
in x86.git

cause my servers hang
after
Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()

after reverting that I got:

initcall 0xffffffff80b947d1 ran for 19 msecs: pci_iommu_init+0x0/0x13()
Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()
hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
hpet0: 3 32-bit timers, 25000000 Hz
initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100() returned 0.
initcall 0xffffffff80b9a465 ran for 7 msecs: hpet_late_init+0x0/0x100()

CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
CPU6 CPU7
0: 86 0 0 0 0 0
1 0 IO-APIC-edge timer
4: 0 0 0 0 0 0
1 838 IO-APIC-edge serial
7: 1 0 0 0 0 0
0 0 IO-APIC-edge
8: 0 0 0 0 0 0
0 0 IO-APIC-edge rtc0

for mcp55, it should already route hpet to ioapic pin2 or the irq0.

YH


2008-01-16 06:51:55

by Ingo Molnar

[permalink] [raw]
Subject: Re: hpet_late_init hang


(Balaji Cc:-ed)

* Yinghai Lu <[email protected]> wrote:

> "
> commit e5ed385fa0d6f35406e3e3ed75e5eb9adeb811df
> Author: Balaji Rao <[email protected]>
> Date: Tue Jan 15 16:53:29 2008 +0100
>
> Assign IRQs to HPET Timers
> "
> in x86.git
>
> cause my servers hang
> after
> Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()

i'm wondering, where does it hang exactly and why?

> after reverting that I got:
>
> initcall 0xffffffff80b947d1 ran for 19 msecs: pci_iommu_init+0x0/0x13()
> Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()
> hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
> hpet0: 3 32-bit timers, 25000000 Hz
> initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100() returned 0.
> initcall 0xffffffff80b9a465 ran for 7 msecs: hpet_late_init+0x0/0x100()
>
> CPU0 CPU1 CPU2 CPU3 CPU4 CPU5
> CPU6 CPU7
> 0: 86 0 0 0 0 0
> 1 0 IO-APIC-edge timer
> 4: 0 0 0 0 0 0
> 1 838 IO-APIC-edge serial
> 7: 1 0 0 0 0 0
> 0 0 IO-APIC-edge
> 8: 0 0 0 0 0 0
> 0 0 IO-APIC-edge rtc0
>
> for mcp55, it should already route hpet to ioapic pin2 or the irq0.

hm, these new bits:

+ /* Assign IRQs statically for legacy devices */
+ hpetp->hp_dev[0].hd_hdwirq = hdp->hd_irq[0];
+ hpetp->hp_dev[1].hd_hdwirq = hdp->hd_irq[1];

seem to be different from where we came from:

- for (i = 2; i < nrtimers; timer++, i++)
- hd.hd_irq[i] = (timer->hpet_config & Tn_INT_ROUTE_CNF_MASK) >>
- Tn_INT_ROUTE_CNF_SHIFT;

Ingo

2008-01-16 08:21:50

by Balaji Rao

[permalink] [raw]
Subject: Re: hpet_late_init hang

On Wednesday 16 January 2008 12:21:33 pm Ingo Molnar wrote:
Hi Ingo,
> * Yinghai Lu <[email protected]> wrote:
> > "
> > commit e5ed385fa0d6f35406e3e3ed75e5eb9adeb811df
> > Author: Balaji Rao <[email protected]>
> > Date: Tue Jan 15 16:53:29 2008 +0100
> >
> > Assign IRQs to HPET Timers
> > "
> > in x86.git
> >
> > cause my servers hang
> > after
> > Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()
>
> i'm wondering, where does it hang exactly and why?
>
> > after reverting that I got:
> >
> > initcall 0xffffffff80b947d1 ran for 19 msecs: pci_iommu_init+0x0/0x13()
> > Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()
> > hpet0: at MMIO 0xfed00000, IRQs 2, 8, 31
> > hpet0: 3 32-bit timers, 25000000 Hz
> > initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100() returned 0.
> > initcall 0xffffffff80b9a465 ran for 7 msecs: hpet_late_init+0x0/0x100()
> >
Looks like IRQ 31 is assigned to timer 3, even without the patch! I wonder who wrote the number 31. But the manual says
that it is zero by default.

I think we should check whether the timer has been allocated an IRQ before proceeding to assign one to it.
Here is a patch that does this.

Yinghai, could you please apply this on top of my patch and check ?

---
Index: linux-2.6/arch/x86/kernel/hpet.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/hpet.c
+++ linux-2.6/arch/x86/kernel/hpet.c
@@ -116,7 +116,8 @@ int is_hpet_enabled(void)
static void hpet_reserve_platform_timers(unsigned long id)
{
struct hpet __iomem *hpet = hpet_virt_address;
- unsigned int nrtimers;
+ struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
+ unsigned int nrtimers, i;
struct hpet_data hd;

nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
@@ -134,10 +135,9 @@ static void hpet_reserve_platform_timers
hd.hd_irq[0] = HPET_LEGACY_8254;
hd.hd_irq[1] = HPET_LEGACY_RTC;

- /*
- * IRQs for the other timers are assigned dynamically
- * in hpet_alloc
- */
+ for (i = 2; i < nrtimers; timer++, i++)
+ hd.hd_irq[i] = (timer->hpet_config & Tn_INT_ROUTE_CNF_MASK) >>
+ Tn_INT_ROUTE_CNF_SHIFT;
hpet_alloc(&hd);
}
#else
Index: linux-2.6/drivers/char/hpet.c
===================================================================
--- linux-2.6.orig/drivers/char/hpet.c
+++ linux-2.6/drivers/char/hpet.c
@@ -852,6 +852,12 @@ int hpet_alloc(struct hpet_data *hdp)

timer = &hpet->hpet_timers[devp - hpetp->hp_dev];

+ /* Check if there's already an IRQ assigned to the timer */
+ if (hdp->hd_irq[i]) {
+ hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
+ continue;
+ }
+
hpet_config = readq(&timer->hpet_config);
irq_bitmap = (hpet_config & Tn_INT_ROUTE_CAP_MASK)
>> Tn_INT_ROUTE_CAP_SHIFT;

---
regards,
balaji rao

2008-01-16 21:39:55

by Yinghai Lu

[permalink] [raw]
Subject: Re: hpet_late_init hang

On Jan 16, 2008 12:34 AM, Balaji Rao <[email protected]> wrote:
> On Wednesday 16 January 2008 12:21:33 pm Ingo Molnar wrote:
> Hi Ingo,
> > * Yinghai Lu <[email protected]> wrote:
> > > "
> > > commit e5ed385fa0d6f35406e3e3ed75e5eb9adeb811df
> > > Author: Balaji Rao <[email protected]>
> > > Date: Tue Jan 15 16:53:29 2008 +0100
> > >
> > > Assign IRQs to HPET Timers
> > > "
> > > in x86.git
> > >
> > > cause my servers hang
> > > after
> > > Calling initcall 0xffffffff80b9a465: hpet_late_init+0x0/0x100()
..
> Looks like IRQ 31 is assigned to timer 3, even without the patch! I wonder who wrote the number 31. But the manual says
> that it is zero by default.
>
> I think we should check whether the timer has been allocated an IRQ before proceeding to assign one to it.
> Here is a patch that does this.
>
> Yinghai, could you please apply this on top of my patch and check ?
>
> ---
> Index: linux-2.6/arch/x86/kernel/hpet.c
> ===================================================================
> --- linux-2.6.orig/arch/x86/kernel/hpet.c
...
>

it works

YH

2008-01-17 15:59:23

by Balaji Rao

[permalink] [raw]
Subject: Re: hpet_late_init hang

On Thursday 17 January 2008 03:09:42 am Yinghai Lu wrote:
> > Looks like IRQ 31 is assigned to timer 3, even without the patch! I wonder who wrote the number 31. But the manual says
> > that it is zero by default.
> >
> > I think we should check whether the timer has been allocated an IRQ before proceeding to assign one to it.
> > Here is a patch that does this.
> >
> > Yinghai, could you please apply this on top of my patch and check ?
> >
> > ---
> > Index: linux-2.6/arch/x86/kernel/hpet.c
> > ===================================================================
> > --- linux-2.6.orig/arch/x86/kernel/hpet.c
> ...
> >
>
> it works
>
Cool!

Ingo, here's the patch with the SOB. Please apply.

regards,
balaji rao

Check if there's an IRQ assigned to the timer before assigning one.

Signed-off-by: Balaji Rao <[email protected]>

Index: linux-2.6/arch/x86/kernel/hpet.c
===================================================================
--- linux-2.6.orig/arch/x86/kernel/hpet.c
+++ linux-2.6/arch/x86/kernel/hpet.c
@@ -116,7 +116,8 @@ int is_hpet_enabled(void)
?static void hpet_reserve_platform_timers(unsigned long id)
?{
????????struct hpet __iomem *hpet = hpet_virt_address;
-???????unsigned int nrtimers;
+???????struct hpet_timer __iomem *timer = &hpet->hpet_timers[2];
+???????unsigned int nrtimers, i;
????????struct hpet_data hd;
?
????????nrtimers = ((id & HPET_ID_NUMBER) >> HPET_ID_NUMBER_SHIFT) + 1;
@@ -134,10 +135,9 @@ static void hpet_reserve_platform_timers
????????hd.hd_irq[0] = HPET_LEGACY_8254;
????????hd.hd_irq[1] = HPET_LEGACY_RTC;
?
-???????/*
-??????? * IRQs for the other timers are assigned dynamically
-??????? * in hpet_alloc
-??????? */
+ ? ? ? for (i = 2; i < nrtimers; timer++, i++)
+??????? ? ? ? hd.hd_irq[i] = (timer->hpet_config & Tn_INT_ROUTE_CNF_MASK) >>
+??????????????? ? ? ? Tn_INT_ROUTE_CNF_SHIFT;
????????hpet_alloc(&hd);
?}
?#else
Index: linux-2.6/drivers/char/hpet.c
===================================================================
--- linux-2.6.orig/drivers/char/hpet.c
+++ linux-2.6/drivers/char/hpet.c
@@ -852,6 +852,12 @@ int hpet_alloc(struct hpet_data *hdp)
?
????????????????timer = &hpet->hpet_timers[devp - hpetp->hp_dev];
?
+???????????????/* Check if there's already an IRQ assigned to the timer */
+???????????????if (hdp->hd_irq[i]) {
+???????????????????????hpetp->hp_dev[i].hd_hdwirq = hdp->hd_irq[i];
+???????????????????????continue;
+???????????????}
+
????????????????hpet_config = readq(&timer->hpet_config);
????????????????irq_bitmap = (hpet_config & Tn_INT_ROUTE_CAP_MASK)
????????????????????????>> Tn_INT_ROUTE_CAP_SHIFT;

2008-01-18 12:41:36

by Ingo Molnar

[permalink] [raw]
Subject: Re: hpet_late_init hang


* Balaji Rao <[email protected]> wrote:

> Ingo, here's the patch with the SOB. Please apply.

thanks - reinstated your original patch and added your fix too. I added:

Signed-off-by: Balaji Rao <[email protected]>
Tested-by: Yinghai Lu <[email protected]>

Ingo