Re: Long timeout when booting >= 2.6.38

From: Christian Hoffmann
Date: Mon May 16 2011 - 15:35:03 EST




Nothing to be sorry about. Thanks for providing the information. If I
decoded the problem correctly then this just unearthed a real long
standing bug. Does the patch below solve the problem ?

Thanks,

tglx

--- linux-2.6.orig/kernel/time/tick-broadcast.c
+++ linux-2.6/kernel/time/tick-broadcast.c
@@ -522,10 +522,11 @@ static void tick_broadcast_init_next_eve
*/
void tick_broadcast_setup_oneshot(struct clock_event_device *bc)
{
+ int cpu = smp_processor_id();
+
/* Set it up only once ! */
if (bc->event_handler != tick_handle_oneshot_broadcast) {
int was_periodic = bc->mode == CLOCK_EVT_MODE_PERIODIC;
- int cpu = smp_processor_id();

bc->event_handler = tick_handle_oneshot_broadcast;
clockevents_set_mode(bc, CLOCK_EVT_MODE_ONESHOT);
@@ -551,6 +552,15 @@ void tick_broadcast_setup_oneshot(struct
tick_broadcast_set_event(tick_next_period, 1);
} else
bc->next_event.tv64 = KTIME_MAX;
+ } else {
+ /*
+ * The first cpu which switches to oneshot mode sets
+ * the bit for all other cpus which are in the general
+ * (periodic) broadcast mask. So the bit is set and
+ * would prevent the first broadcast enter after this
+ * to program the bc device.
+ */
+ tick_broadcast_clear_oneshot(cpu);
}
}


Hi,

I booted a couple of times now, and the problem seems solved.

[ 1.423793] TCP reno registered
[ 1.423805] UDP hash table entries: 4096 (order: 5, 131072 bytes)
[ 1.423847] UDP-Lite hash table entries: 4096 (order: 5, 131072 bytes)
[ 1.423944] NET: Registered protocol family 1
[ 1.423953] pci 0000:00:01.0: MSI quirk detected; subordinate MSI disabled
[ 2.300205] pci 0000:01:05.0: Boot video device
[ 2.300218] PCI: CLS 64 bytes, default 64
[ 2.300262] Trying to unpack rootfs image as initramfs...
[ 2.438632] Freeing initrd memory: 10540k freed
[ 2.442368] PCI-DMA: Disabling AGP.
[ 2.442501] PCI-DMA: aperture base @ c0000000 size 65536 KB
[ 2.442503] PCI-DMA: using GART IOMMU.
[ 2.442505] PCI-DMA: Reserving 64MB of IOMMU area in the AGP aperture
[ 2.446264] audit: initializing netlink socket (disabled)

Thanks a lot!!!

Kind regards,
Chris
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