fun with acpi (IRQ 0 fix)

[subliminal_boy_9]

Ran across one that I don't see documented anywhere, so I thought it would be good to share.

If, during the course of your testing, you find that BTTV is not finding all of your inputs, please check to see that your card resources are being allocated correctly. If you check dmesg, you may find a line similar to the one below:

Code: Select all

bttv1: Bt878 (rev 17) at 0000:03:09.0, irq: 0, latency: 32, mmio: 0xeeafc000

Notice the IRQ number is set to zero. The output from lspci shows that the system recognizes and can find all your chips, but dmesg tells you that the board is not set up right (hence irq 0 in use).

The solution to this is not in trying to force the card type when inserting the module (i.e., modprobe bttv gbuffers=16 card=xx,xx,xx,xx). Instead, the solution lies in your bios options and your kernel compilation. Gentoo users (like myself) will stumble upon this more frequently, as you have complete control over your kernel right out of the box. Those that are using pre-compiled kernels likely won't run into something like this as often.

1) Turn off Plug and Play in your bios. It is a counter intuitive setting, but it should be off whether the machine is running linux or Windows 2000 or later.

2) Compile a kernel with ACPI support and install it with the proper entry to your bootloader.

3) Set your bios options to enable ACPI support.

4) Reboot and enjoy.

[zoneminder]

Thanks for the tip. I'm about to get a new box after Xmas (hopefully when they are cheaper) so I'll keep an eye out for this.

Phil