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, Harald
//Peter