From mboxrd@z Thu Jan 1 00:00:00 1970 From: lorenzo.pieralisi@arm.com (Lorenzo Pieralisi) Date: Mon, 26 Oct 2015 10:05:41 +0000 Subject: [PATCH v2 4/5] drivers: firmware: psci: add extended stateid power_state support In-Reply-To: References: <1436375811-10529-1-git-send-email-lorenzo.pieralisi@arm.com> <3982126.UybqODJKJo@wuerfel> <20151023104457.GA9309@red-moon> <7012327.dvizHt4W5S@wuerfel> <20151023113618.GA29008@red-moon> Message-ID: <20151026100541.GC8263@red-moon> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Fri, Oct 23, 2015 at 08:10:30AM -0700, Kevin Hilman wrote: > On Fri, Oct 23, 2015 at 4:36 AM, Lorenzo Pieralisi > wrote: > > On Fri, Oct 23, 2015 at 12:55:34PM +0200, Arnd Bergmann wrote: > >> On Friday 23 October 2015 11:44:58 Lorenzo Pieralisi wrote: > >> > > >> > Problem with Qemu emulation is that it does not emulate the PSCI 1.0 > >> > specs correctly (it does not even consider PSCI 1.0 functions proper PSCI > >> > calls), I tested it and I think we should update Qemu as we > >> > did with KVM kernel code instead of working around it by dodging the > >> > problem in the PSCI implementation by adding code that checks the > >> > PSCI version before issuing the PSCI calls through the respective > >> > conduit. > >> > > >> > Thoughts appreciated. > >> > >> I think we really cannot break existing qemu installations, but need > >> a way to detect whether we are dealing with a broken qemu (and warn > >> about that) or with a working PSCI implementation. > >> > >> Fixing qemu is of course a good idea, but it's not sufficient. > > > > I will patch the PSCI back-end in the kernel to issue PSCI_FEATURES calls > > only if the PSCI version detected is 1.0, therefore solving the issue, it > > is not necessary according to the specs, but that's belt and braces > > and sorts this niggle out. > > > > I will send a patch shortly to be applied on top of arm-soc drivers/psci. > > Thanks! > > In parallel, since you understandn better what qemu is/isn't doing, > can you ping the qemu folks about this bug? Yes, I will help them implement PSCI 1.0 support so that we can upgrade smoothly. Thanks Kevin ! Lorenzo