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Re: [Qemu-devel] [PATCH 7/7] ahci: work around bug with level interrupts
From: |
Aurelien Jarno |
Subject: |
Re: [Qemu-devel] [PATCH 7/7] ahci: work around bug with level interrupts |
Date: |
Tue, 1 Feb 2011 18:06:14 +0100 |
User-agent: |
Mutt/1.5.18 (2008-05-17) |
On Tue, Feb 01, 2011 at 05:53:43PM +0100, Alexander Graf wrote:
>
> On 01.02.2011, at 17:34, Aurelien Jarno wrote:
>
> > On Tue, Feb 01, 2011 at 03:51:32PM +0100, Alexander Graf wrote:
> >> When using level based interrupts, the interrupt is treated the same as an
> >> edge triggered one: leaving the line up does not retrigger the interrupt.
> >>
> >> In fact, when not lowering the line, we won't ever get a new interrupt
> >> inside
> >> the guest. So let's always retrigger an interrupt as soon as the OS ack'ed
> >> something on the device. This way we're sure the guest doesn't starve on
> >> interrupts until someone fixes the actual interrupt path.
> >
> > Given this issue mostly concerns x86 and not other architectures where
> > the SATA emulation can probably be used, what about putting the two
> > versions of the codes like in i8259.c:
> >
> > | * all targets should do this rather than acking the IRQ in the cpu */
> > | #if defined(TARGET_MIPS) || defined(TARGET_PPC) || defined(TARGET_ALPHA)
> >
> > The list of architectures here is reduced given the few architectures
> > that actually use the i8259, so for ahci.c it should probably be #if not
> > defined(TARGET_I386) instead.
>
> Because then we'd have to build the ahci code conditionally on the
> architecture. Right now it builds into libhw :)
If we want to keep it in libhw, it's probably better to disable it on
other architectures than i386.
--
Aurelien Jarno GPG: 1024D/F1BCDB73
address@hidden http://www.aurel32.net
[Qemu-devel] [PATCH 5/7] ahci: Implement HBA reset, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 4/7] ahci: send init d2h fis on fis enable, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 6/7] ahci: make number of ports runtime determined, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 3/7] ahci: split ICH and AHCI even more, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 1/7] ahci: split ICH9 from core, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 2/7] ahci: add license header in ahci.h, Alexander Graf, 2011/02/01
[Qemu-devel] [PATCH 7/7] ahci: work around bug with level interrupts, Alexander Graf, 2011/02/01