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SubjectRe: PANIC: early exception 08 rip 246:10 error ffffffff810251b5 cr2 0
Valdis.Kletnieks@vt.edu wrote:
> On Mon, 26 Oct 2009 11:34:20 PDT, Justin Mattock said:
>
>
>> I can't seem to locate a right mailing list
>> for ieee1394 for Linux. Anyways here is a
>> url to flickr which has the image of the PANIC:
>> http://www.flickr.com/photos/44066293@N08/4046711653/
>> (hopefully you don't need to sign up to view)
>>
>> As for the problem, interesting thing here is if I add
>> a printk to:
>>
>> if ((class == 0xffffffff))
>> printk(KERN_BUG "init_ohci1394_dma: finished initializing OHCI DMA\n");
>> continue; /* No device at this func */
>>
>> the system will boot-up, and the PANIC will not occur.
>>
>
> Note that just sticking a printk in there without a { } pair enclosing
> the printk and continue will change the semantics drastically - if the
> conditional is true, it will do the printk instead of continuing. And
> possibly more important, the continue just became unconditional.
>
> What *exactly* does your code look like now?
>
as of now in init_ohci1394_dma.c
I did:



void __init init_ohci1394_dma_on_all_controllers(void)
{
int num, slot, func;
if (!early_pci_allowed())
return;
/* Poor man's PCI discovery, the only thing we can do at early boot */
for (num = 0; num < 32; num++) {
for (slot = 0; slot < 32; slot++) {
for (func = 0; func < 8; func++) {
u32 class = read_pci_config(num,slot,func,
PCI_CLASS_REVISION);
if ((class == 0xffffffff))
+ printk(KERN_DEBUG "putting a printk here keeps the
machine from a panic\n");
continue; /* No device at this func */
if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
continue; /* Not an OHCI-1394 device */
init_ohci1394_controller(num, slot, func);
break; /* Assume one controller per device */
}
}
}
printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI
DMA\n");
}

interesting thing here, is I just was wanting to see were this thing was
crashing. when adding this in(above) Ill see a long string during boot
for a few seconds and then the machine boots up.
Now if I add a printk(example below) to here:



void __init init_ohci1394_dma_on_all_controllers(void)
{
int num, slot, func;
if (!early_pci_allowed())
return;
/* Poor man's PCI discovery, the only thing we can do at early boot */
for (num = 0; num < 32; num++) {
for (slot = 0; slot < 32; slot++) {
for (func = 0; func < 8; func++) {
u32 class = read_pci_config(num,slot,func,
PCI_CLASS_REVISION);
if ((class == 0xffffffff))
continue; /* No device at this func */
if (class>>8 != PCI_CLASS_SERIAL_FIREWIRE_OHCI)
+ printk(KERN_DEBUG "putting a printk here keeps the
machine from a panic\n");
continue; /* Not an OHCI-1394 device */
init_ohci1394_controller(num, slot, func);
break; /* Assume one controller per device */
}
}
}
printk(KERN_INFO "init_ohci1394_dma: finished initializing OHCI
DMA\n");
}


In dmesg I will see maybe 5 to 10 debug messages and then
onto init_ohci1394_initialize.
keep in mind I'm not familiar with any of this, but just looking
at the code I see 0xffffffff and searching(google) tells me
that that's something with 32bit, should maybe there be something
with 0xffffffffffffffffff 64bit?
Justin P. Mattock




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