[LinuxBIOS] PIC mode or APIC mode

Beneo beneo at comcast.net
Fri Apr 13 19:48:25 CEST 2007

I was working this Broadcom bcm 5785 based reference board with LinuxBIOS, I 
have a NIC interrupt related issue, the eth0 DHCP detection always fail, so 
I can not get an IP address for that NIC. I did what Peter Stuge suggested 
to dump the /proc/interrupts. It turns out the Linux is using PIC mode, not 
APIC mode. (Linux report multiple CPUs, so I assume Linux took MP Table 
somewhat correctly)

I checked chipset setting, the APIC indeed is enabled. I don't see Linux is 
doing anything for PIC or APIC, I assume Linux kernel will correctly 
initialize PIC or APIC depends on MP Table reporting. right?

If anybody has any idea on why Linux is running at PIC mode, Please let me 
know. I will be very appreciated.



--- LinuxBIOS /proc/interrupts look like this, it is in PIC mode --
[root at localhost root]# cat /proc/interrupts
           CPU0       CPU1
  0:      13538       1521          XT-PIC  timer
  1:          0          0          XT-PIC  keyboard
  2:          0          0          XT-PIC  cascade
  4:        302        153          XT-PIC  serial
  8:          1          0          XT-PIC  rtc
 14:       4729       1803          XT-PIC  ide0
NMI:          0          0
LOC:      14778      14897
ERR:      21478
MIS:          0

--- When using factory BIOS, the cat /proc/interrupts looks like this, it is 
in APIC mode.
[root at localhost root]# cat /proc/interrupts
           CPU0       CPU1
  0:        719       8393    IO-APIC-edge  timer
  1:          0          4    IO-APIC-edge  keyboard
  2:          0          0          XT-PIC  cascade
  4:          5        505    IO-APIC-edge  serial
  8:          0          1    IO-APIC-edge  rtc
 10:          0          2   IO-APIC-level  ehci-hcd, usb-ohci, usb-ohci
 12:          1          6    IO-APIC-edge  PS/2 Mouse
 14:       1433       5111    IO-APIC-edge  ide0
 38:          7        112   IO-APIC-level  eth0
NMI:          0          0
LOC:       9020       8869
ERR:          0
MIS:          0

----- Original Message -----
From: "Peter Stuge" <stuge-linuxbios at cdy.org>
To: <linuxbios at linuxbios.org>
Sent: Monday, April 09, 2007 10:23 AM
Subject: Re: [LinuxBIOS] IDE become readonly, why?

> On Mon, Apr 09, 2007 at 10:02:15AM -0700, Beneo wrote:
>> For the RTC patch, it is porting for a SMSC SIO, I didn't see
>> LinuxBIOS has this SIO porting. The part number is SCH--4703, I
>> don't know how to contribute it to LinuxBIOS tree.
> Ahh! It's new code, sorry, forgot that.
> Please have a look at http://linuxbios.org/Development_Guidelines to
> learn most if not all you need to know to submit a patch.
> Also, when submitting patches, please make sure they apply cleanly to
> the very latest revision of the tree.
> The simplest way to do this is to always keep your own tree updated
> by running svn up now and then, or when you see a new revision
> announced on the list. After an update, there may be conflicts that
> need to be resolved manually by you if you have been working on code
> that was also changed in the new revision.
>> I haven't get the chance to take look at my NIC issue yet, I will
>> certainly check the interrupt when I get the chance.
> Feel free to ask the list if you run into trouble!
> //Peter
> -- 

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