[coreboot] ACPI on m57sli v1.0

Harald Gutmann harald.gutmann at gmx.net
Sat Jul 4 11:02:36 CEST 2009

On Thursday 02 July 2009 23:26:34 Peter Stuge wrote:
> Harald Gutmann wrote:
> > > Is the port interrupt-driven, or polling, on your system, Andreas?
> >
> > Here on my system it says also polling, like on Andreas system.
> > What is the difference between interrupt driven and polling?
> Interrupt driven means the port has an interrupt assigned to it, and
> that communication over the port is event based.
> Polling means there is a timer running in the kernel which will check
> the port for activity every few milliseconds or something.
> > On vendor bios it is interrupt-driven.
> > Is an ACPI part missing to get it interrupt driven?
> I think so, yes.
So, I've added the missing ACPI part, but it seems that some more work is 
needed to get parport interrupt driven working.

The dmesg output changes a little bit, and also mentions IRQ7, but lp0 is 
still noticed as polling:
[  745.974254] parport_pc 00:04: reported by Plug and Play ACPI
[  745.974371] parport0: PC-style at 0x378 (0x778) [PCSPP,TRISTATE]
[  746.104129] parport0: irq 7 detected
[  751.914593] ppdev: user-space parallel port driver
[  770.953504] lp0: using parport0 (polling).

I think that it is necessary to set some irq bit to get it working fine. This 
idea is from the vendors dsdt.asl [1] and the LPT1 (starting at line 5374) 
section of it.
Looking at that part there is something noticed about INTR which could be the 
IRQ bit I assume that this is needed.

Can anyone help me out here a little bit?

[1] http://coreboot.pastebin.com/f3e965943

Kind regards,

> //Peter

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