On Saturday 04 July 2009 11:02:36 Harald Gutmann wrote:
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.
I just did a mistake and set no address in the IO Section.
There's already another patch on the list (which was filtered by my spam-filter, and therefore I did the job again). The difference between my patch, and the one from Andreas are minimal, but I added the ECP device which is necessary to get Parport full functional (hopefully I did everything correct, as I can't test this without Parport devices.)
The attached patch activates changes the LPT port from polling to interrupt- driven, and should be fine.
Signed-off-by: Harald Gutmann harald.gutmann@gmx.net
Kind regards, Harald
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
//Peter