From: Tim Hockin <thockin@hockin.org>
To: Pierre Ossman <drzeus-list@drzeus.cx>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: Re: APIC, changing level/edge interrupt
Date: Sat, 1 Jan 2005 12:24:50 -0800 [thread overview]
Message-ID: <20050101202450.GA19360@hockin.org> (raw)
In-Reply-To: <41D6C81F.1090106@drzeus.cx>
On Sat, Jan 01, 2005 at 04:56:15PM +0100, Pierre Ossman wrote:
> >BIOS should set this up. Maybe ACPI has a way to do this?
> Should doesn't always mean that it actually does ;)
Of course. My point was that if it does not, it's a bug in the BIOS.
> But since BIOS can configure the APIC then the kernel should be able to
Of course, but the kernel has no way to know whether a device should be
edge or level triggered unless you have a driver for that device. And
even if you do, I don't know that there is an API in kernel to say
set_irq_mode(IRQ_EDGE) (though there could be).
> What is the default mode and what does the XT-PIC expect? (it works fine
> with the apic disabled).
I think default is PIC-compatible which is edge by default. I think. I
don;t have the book here.
> ACPI might have some functions to configure the APIC correctly but right
> now the connection between ACPI and drivers is rather weak (non-existant
> for this driver) so that's not really a viable solution when testing.
> Might be a good long term solution though.
I know ACPI can get the information with the _PRS and _CRS methods. The
OSPM core should probably be re-programming the (A)PIC appropriately. Of
course, that depends on the BIOS vendor getting the ACPI correct, too.
next prev parent reply other threads:[~2005-01-01 20:25 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2004-12-28 17:27 APIC, changing level/edge interrupt Pierre Ossman
2005-01-01 5:49 ` Tim Hockin
2005-01-01 15:56 ` Pierre Ossman
2005-01-01 20:24 ` Tim Hockin [this message]
2005-01-01 21:22 ` Pierre Ossman
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