[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 0/2] Remove CP15 timer from the device tree if K
From: |
Peter Maydell |
Subject: |
Re: [Qemu-devel] [PATCH 0/2] Remove CP15 timer from the device tree if KVM is used without in-kernel irqchip |
Date: |
Thu, 25 Jun 2015 13:27:56 +0100 |
On 25 June 2015 at 13:14, Pavel Fedin <address@hidden> wrote:
>> If we want to support "KVM but without in-kernel irqchip" I would
>> really prefer that we did it this way, by implementing an ABI for
>> letting the kernel tell us about the generic timer interrupts
>
> Yes, but:
> 1. This would work only for newer kernels.
> 2. This little patch allows to work on older kernels, at least somehow.
I don't think "needs a newer kernel" is a particularly serious
restriction here.
Also some boards have no fallback timer device at all (notably
"virt", so generic-timer *has* to work.
>> IIRC chazy had a hacked-together patch for that at some point.
>
> Who is it? Where can i find it?
I was misremembering. That's Christoffer Dall, and in fact he
didn't write any code, he just suggested that it was possible.
>> Is hardware with no working VGIC really prevalent enough that
>> it's worth adding support? Presumably the performance isn't going
>> to be very good...
>
> At least RaspberryPi 2, as far as i know. Also i am testing on some
> Samsung proprietary HW which has the same problem.
I hope you have fed back to the h/w designers that they need
to fix this for the next revision :-)
thanks
-- PMM