IRQ-conflicts

QBasti · 05-17-2009, 03:09 PM

hey there,

I have a very old pc running some important software (allergology)
i bought almost identical hardware and backed up the disks using "dd". all interfaces identically plugged in the backup-pc stops during boot right here:

Code:

Configuring serial ports...
ttyS4 (irq = 10) is a [...]
ttyS5 (irq = 10) is a [...]

(i dont have the exact code since the pc doesnt have a internet connection)
(... is always identical)

the problem seems to be caused by a PCI-card providing an serial interface connected via a breakout cable to another pc. if that cable is not plugged in the part is skipped and the pc is booting fine..

the original-pc says

Code:

Configuring serial ports...
ttyS4 (irq = 10) is a [...]
ttyS5 (irq = 10) is a [...]
ttyS6 (irq = 10) is a [...]
ttyS7 (irq = 10) is a [...]

and continues to boot just fine..

i compared /etc/interrupts/, and it seems the backup-pc is also using IRQ 10 for the network-card. how can i disable that IRQ-Sharing? (my guess is, that the cards are too old to support IRQ-Sharing)
is it possible to put eth0 separately on IRQ 11 or something?

Thanks for any help

EDIT:

BIOS settings are identical, too

H_TeXMeX_H · 05-17-2009, 03:29 PM

I think in most BIOSes you can assign IRQs yourself if you need to, especially for serial ports.

Another possible option is to check the pci= options, irq options, acpi and apic options, and try some of them out that seem reasonable, there are many possible options:

http://www.kernel.org/doc/Documentat...parameters.txt

QBasti · 05-18-2009, 12:24 AM

hey there,

i can only choose under "power management" "IRQ 10" between Monitor or Ignore or under "PCI Configuration" "IRQ 10" PCI&PnP or ISA. ISA would be manually assigning the addresses right?

thanks for the link, i'll try to find the right parameters

H_TeXMeX_H · 05-18-2009, 05:20 AM

I think so. I mean it's allowing you to manually set IRQs for various interfaces. It doesn't always work right tho.

QBasti · 05-18-2009, 09:12 AM

well I dont understand how I can specifically set them. If i select ISA in the BIOS, where is the setting for the IRQ? is it jumpered directly on the card or something?

H_TeXMeX_H · 05-18-2009, 10:14 AM

What motherboard is this ? Does it have a manual somewhere, maybe it gives some hints in there about if it can be done.

NeddySeagoon · 05-18-2009, 01:56 PM

QBasti,

PCI devices are required to share IRQs - they are designed that way as a result of running out of IRQs on ISA systems. As its a single PCI card, having all the serial ports on the same IRQ is not an issue.
The on board serial ports (0..3) will share IRQs 3 and 4, with all the usual ISA horrors.

The ... which you omitted is the type of UART, its not useful for fixing the problem.

The only way to attempt to move the PCI card to another IRQ is to plug it into a different PCI slot in the motherboard. This does not always work.
You said

Quote:

the problem seems to be caused by a PCI-card providing an serial interface connected via a breakout cable to another pc. if that cable is not plugged in the part is skipped and the pc is booting fine.

Is the boot process paused waiting for input from the other PC connected by that cable. If you connect the cable after its booted is everything ok?

QBasti · 05-18-2009, 02:39 PM

Hey,

I dont think its waiting for any response, since the original PC is not waiting either, it wouldn't make any sense for it to wait, since the other PC is not essential for booting or any other system jobs, only later for the software..

if I plug in the cable after booting, there's no connection to the other pc, although no error message is presented in dmesg...

EDIT:

when it stops booting, the keyboard and everything else is hung up, too. (e.g. the caps lock light stops working)...
also there's an SCSI-RAID-controller plugged in, might that have anything to do with it? (the raid is always workin fine though)

cloud9repo · 05-18-2009, 02:50 PM

buy an os, things tricky

QBasti · 05-19-2009, 09:43 AM

well i'd love to buy a new os and just throw out the old one, but the software wont work on anything else..

well i switched the pci-slots, eth0 is on IRQ 11 now, but its still the same problem. if I boot without the cable connected and then plug it in, I can do

Code:

cat /dev/ttyS4
cat dev/ttyS5

but

Code:

cat /dev/ttyS6

freezes up the whole PC...

NeddySeagoon · 05-19-2009, 12:48 PM

QBasti,

cat /dev/ttyS6 attempts to read characters from that serial port. I'm not sure if its a blocking read (waits for someting to read) or not. Even so, you should be able to change to another VT and log in again.

What does lspci say about your system?
Post the output here and I'll see what google knows about your card.

Your raid is unlikely to be an issue.

QBasti · 05-26-2009, 09:33 AM

sorry for the late response..

lspci says:

Code:

...
00:09.0 Serial Controller: Timedia Technology Co Ltd: Unknown device 7168 (rev 1)
...

why is the controller properly addressed but "unknown"?

NeddySeagoon · 05-27-2009, 02:10 PM

QBasti,

Thats a bit unfortunate. Thats not enough information for Google.
Run

Code:

lspci -n

and post the line you get starting 00:09.0.
The numbers are the Vendor and Device IDs, which google will know.

QBasti · 05-28-2009, 03:24 AM

hey there,

lspci -n says:

Code:

00:09.0 Class 0700: 1409:7168 (rev 01)

NeddySeagoon · 06-01-2009, 03:02 PM

QBasti,

This page says the the normal kernel driver takes care of your card. Its odd that that page talks about the parallel port driver and mentions lots of devices with UARTs.

The default kernel config provides for four serial ports, ttyS0 .. ttyS3. You will need to change this option to 8 and rebuild your kernel to see your other serial ports.

Code:

  │ │    <*> 8250/16550 and compatible serial support                      │ │  
  │ │[*]   Console on 8250/16550 and compatible serial port            │ │  
  │ │    (32) Maximum number of 8250/16550 serial ports                    │ │  
  │ │    (4) Number of 8250/16550 serial ports to register at runtime      │ │  
  │ │[*] Extended 8250/16550 serial driver options                     │ │  
  │ │[*]   Support more than 4 legacy serial ports                     │ │  
  │ │[*]   Support for sharing serial interrupts