Re: [LAU] Thinkpad R60 for Audio Update - Firewire Conflicts with Audio

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Robin Gareus wrote:

mea wrote:
Hi,
Sorry to bump into the thread like this, but I have 3+ year old R40 and
I never managed to make it work with my firewire sound card under linux,
I think mainly because of> cat /proc/interrupts
 0:    6674809          XT-PIC  timer
  1:         24          XT-PIC  i8042
  2:          0          XT-PIC  cascade
  6:          3          XT-PIC  floppy
  8:          1          XT-PIC  rtc
  9:         48          XT-PIC  acpi
 11:    1744806          XT-PIC  uhci_hcd:usb1, uhci_hcd:usb2,
uhci_hcd:usb3, ehci_hcd:usb4, yenta, ohci1394, Intel 82801DB-ICH4, eth0,
radeon@pci:0000:01:00.0
 12:         35          XT-PIC  i8042
 14:      27840          XT-PIC  ide0
 15:         20          XT-PIC  ide1
NMI:          0
ERR:          0

As you can see, 11 is loaded. My question: In BIOS I see letters(A,B,
etc) all assigned to 11. Is it safe to try to change them?

yes, in the worst case you just need to reboot and re-set them..

(hihi; if you dual boot: windows might find some new devices after
flipping those around; prepare to jockey (not mount) the driver CD/DVD)

ABCD usually correspond do the PCI irq wires . aehm striplines or
signals. ;) - some bios allow to choose "[voltage]level" or "edge" IRQ
detection. - not sure if and how that affects rt-linux. i use edge
detection.
If I recall this correctly, level detection is better because it allows for shared interrupts. The interrupt line is pulled high by any device that wants to generate an interrupt. As long as the interrupt line is high, the CPU should execute an interrupt handler. This means that if device A and device B both are connected to the same interrupt line, and both generate an interrupt simultanously they both pull the interrupt line up. The CPU detects this and starts the interrupt service routine that handles either A or B. The device that was handled (e.g. A) stops pulling the line up, which normally exits the interrupt state. But since in this case there is another device with an unhandled interrupt (i.e. B), the doesn't go up and the CPU does another round of interrupt handling.

But it has been a long time since I've been into this...

Pieter


assiging each letter to a different IRQ number and checking the output
of /proc/interrupts seems like a good idea.  try IRQ 3,5,9,11 for example.

you might still be unlucky: the firewire device might share the "wire"
with some other [inconvenient] device(s).

robin
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