From: Paolo Bonzini <pbonzini@redhat.com>
To: Liu Ping Fan <qemulist@gmail.com>
Cc: Jan Kiszka <jan.kiszka@siemens.com>,
qemu-devel@nongnu.org, Anthony Liguori <anthony@codemonkey.ws>
Subject: Re: [Qemu-devel] [PATCH 2/2] hpet: inverse polarity when pin above ISA_NUM_IRQS
Date: Sun, 25 Aug 2013 08:44:00 +0200 [thread overview]
Message-ID: <5219A7B0.2070208@redhat.com> (raw)
In-Reply-To: <1377396984-17706-2-git-send-email-pingfank@linux.vnet.ibm.com>
Il 25/08/2013 04:16, Liu Ping Fan ha scritto:
> According to hpet spec, hpet irq is high active. But according to
> ICH spec, there is inversion before the input of ioapic. So the OS
> will expect low active on this IRQ line.(And this is observed on
> bare metal).
>
> We fold the emulation of this inversion inside the hpet logic.
>
> Signed-off-by: Liu Ping Fan <pingfank@linux.vnet.ibm.com>
> ---
> kernel has a bug with ioapic, refer to
> https://lkml.org/lkml/2013/8/23/98
> With all these patch, linux-2.6/Documentation/timers/hpet_example.c can work
> on qemu
Can you explain "in qemu q35 machine ioapic's ioredtbl[x] can never be
set as low-active, even if the hpet driver registered it"?
Paolo
next prev parent reply other threads:[~2013-08-25 6:44 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-25 2:16 [Qemu-devel] [PATCH 1/2] hpet: entitle more irq pins for hpet Liu Ping Fan
2013-08-25 2:16 ` [Qemu-devel] [PATCH 2/2] hpet: inverse polarity when pin above ISA_NUM_IRQS Liu Ping Fan
2013-08-25 6:44 ` Paolo Bonzini [this message]
2013-08-26 2:49 ` liu ping fan
2013-08-25 6:45 ` [Qemu-devel] [PATCH 1/2] hpet: entitle more irq pins for hpet Paolo Bonzini
2013-08-26 2:53 ` liu ping fan
2013-08-26 7:59 ` Paolo Bonzini
2013-08-26 8:30 ` liu ping fan
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