From: Sudeep Holla <sudeep.holla@arm.com>
To: Ulf Hansson <ulf.hansson@linaro.org>
Cc: "Rafael J . Wysocki" <rafael@kernel.org>,
Sudeep Holla <sudeep.holla@arm.com>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Thomas Gleixner <tglx@linutronix.de>,
Maulik Shah <quic_mkshah@quicinc.com>,
Daniel Lezcano <daniel.lezcano@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/3] arm64: smp: Implement cpus_has_pending_ipi()
Date: Mon, 6 Oct 2025 15:41:40 +0100 [thread overview]
Message-ID: <20251006-spiked-beige-gecko-6d8748@sudeepholla> (raw)
In-Reply-To: <CAPDyKFoz4P6cZWNA-omNtF3XqKKciC07aVXBTVQp8ueyyYxmxA@mail.gmail.com>
On Mon, Oct 06, 2025 at 02:22:49PM +0200, Ulf Hansson wrote:
> On Mon, 6 Oct 2025 at 12:54, Sudeep Holla <sudeep.holla@arm.com> wrote:
> >
> > 2. I understand this is intended for the DragonBoard 410c, where the firmware
> > can’t be updated. However, ideally, the PSCI firmware should handle checking
> > for pending IPIs if that’s important for the platform. The firmware could
> > perform this check at the CPU PPU/HW level and prevent entering the
> > state if needed.
>
> I think this is exactly what is happening on Dragonboard 410c (see the
> stats I shared in the commit message in patch3).
>
> The PSCI FW refuses to enter the suggested idlestate and the call fails.
>
Ah OK, the PSCI FW is doing the job correctly, we are just attempting to
reduce the failures by catching few cases earlier in the OSPM itself ?
Sure it only reduces the failures but it can't eliminate those as IPI might
be issued after this check in the OSPM. I understand the call to firmware
can be prevented.
--
Regards,
Sudeep
next prev parent reply other threads:[~2025-10-06 14:41 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-03 15:02 [PATCH 0/3] pmdomain: Improve idlestate selection for CPUs Ulf Hansson
2025-10-03 15:02 ` [PATCH 1/3] smp: Introduce a weak helper function to check for pending IPIs Ulf Hansson
2025-10-03 15:02 ` [PATCH 2/3] arm64: smp: Implement cpus_has_pending_ipi() Ulf Hansson
2025-10-06 10:54 ` Sudeep Holla
2025-10-06 12:22 ` Ulf Hansson
2025-10-06 14:41 ` Sudeep Holla [this message]
2025-10-10 8:03 ` Ulf Hansson
2025-10-06 15:55 ` Marc Zyngier
2025-10-10 8:30 ` Ulf Hansson
2025-10-10 9:48 ` Marc Zyngier
2025-10-10 9:55 ` Mark Rutland
2025-10-17 14:01 ` Thomas Gleixner
2025-10-20 13:15 ` Ulf Hansson
2025-10-03 15:02 ` [PATCH 3/3] pmdomain: Extend the genpd governor for CPUs to account for IPIs Ulf Hansson
2025-10-06 15:36 ` [PATCH 0/3] pmdomain: Improve idlestate selection for CPUs Sudeep Holla
2025-10-10 7:52 ` Ulf Hansson
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