From: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
To: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Martin Peres <martin.peres@linux.intel.com>,
Tomi Sarvela <tomi.p.sarvela@intel.com>,
Marc Zyngier <marc.zyngier@arm.com>,
jeffy.chen@rock-chips.com
Subject: Re: [PATCH] x86/hpet: Cure interface abuse in the resume path
Date: Tue, 1 Aug 2017 00:22:17 +0200 [thread overview]
Message-ID: <0c0aa39d-48e6-81fd-f189-79272b0e369d@intel.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1707312158590.2287@nanos>
On 7/31/2017 10:07 PM, Thomas Gleixner wrote:
> The HPET resume path abuses irq_domain_[de]activate_irq() to restore the
> MSI message in the HPET chip for the boot CPU on resume and it relies on an
> implementation detail of the interrupt core code, which magically makes the
> HPET unmask call invoked via a irq_disable/enable pair. This worked as long
> as the irq code did unconditionally invoke the unmask() callback. With the
> recent changes which keep track of the masked state to avoid expensive
> hardware access, this does not longer work. As a consequence the HPET timer
> interrupts are not unmasked which breaks resume as the boot CPU waits
> forever that a timer interrupt arrives.
>
> Make the restore of the MSI message explicit and invoke the unmask()
> function directly. While at it get rid of the pointless affinity setting as
> nothing can change the affinity of the interrupt and the vector across
> suspend/resume. The restore of the MSI message reestablishes the previous
> affinity setting which is the correct one.
>
> Fixes: bf22ff45bed6 ("genirq: Avoid unnecessary low level irq function calls")
> Reported-by: Martin Peres <martin.peres@linux.intel.com>
> Reported-by: Tomi Sarvela <tomi.p.sarvela@intel.com>
> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
> Cc: jeffy.chen@rock-chips.com
> Cc: Marc Zyngier <marc.zyngier@arm.com>
> Cc: Peter Ziljstra <peterz@infradead.org>
> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
ACK
next prev parent reply other threads:[~2017-07-31 22:22 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-31 20:07 [PATCH] x86/hpet: Cure interface abuse in the resume path Thomas Gleixner
2017-07-31 22:22 ` Rafael J. Wysocki [this message]
2017-08-01 7:30 ` Tomi Sarvela
2017-08-01 7:43 ` Thomas Gleixner
2017-08-01 8:21 ` Tomi Sarvela
2017-08-01 10:59 ` Thomas Gleixner
2017-08-01 11:07 ` [tip:x86/urgent] " tip-bot for Thomas Gleixner
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