From: marc.zyngier@arm.com (Marc Zyngier)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 5/5] irqchip: gicv3-its: add support for power down
Date: Fri, 30 Jan 2015 19:23:00 +0000 [thread overview]
Message-ID: <54CBDA14.3010503@arm.com> (raw)
In-Reply-To: <1422604009-9248-6-git-send-email-wuyun.wu@huawei.com>
On 30/01/15 07:46, Yun Wu wrote:
> Configurations of an ITS cannot be changed if the ITS is in an
> active status, so it might not be safe to perform a soft reboot
> with all the active ITSes un-disabled, etc. kexec.
>
> This patch will make sure all the active ITSes disabled before
> enabling them again without resetting ITS hardware.
And what happens if the kernel crashes or gets rebooted from a watchdog?
Or if the bootloader messes things up? The ITS is in an unknown state
when we start again.
Wouldn't it be better to address this instead? Enforcing an safe initial
state seems a better solution that relying on mechanisms that may not be
relevant for all cases.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
WARNING: multiple messages have this Message-ID (diff)
From: Marc Zyngier <marc.zyngier@arm.com>
To: Yun Wu <wuyun.wu@huawei.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"jason@lakedaemon.net" <jason@lakedaemon.net>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-arm-kernel@lists.infradead.org"
<linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 5/5] irqchip: gicv3-its: add support for power down
Date: Fri, 30 Jan 2015 19:23:00 +0000 [thread overview]
Message-ID: <54CBDA14.3010503@arm.com> (raw)
In-Reply-To: <1422604009-9248-6-git-send-email-wuyun.wu@huawei.com>
On 30/01/15 07:46, Yun Wu wrote:
> Configurations of an ITS cannot be changed if the ITS is in an
> active status, so it might not be safe to perform a soft reboot
> with all the active ITSes un-disabled, etc. kexec.
>
> This patch will make sure all the active ITSes disabled before
> enabling them again without resetting ITS hardware.
And what happens if the kernel crashes or gets rebooted from a watchdog?
Or if the bootloader messes things up? The ITS is in an unknown state
when we start again.
Wouldn't it be better to address this instead? Enforcing an safe initial
state seems a better solution that relying on mechanisms that may not be
relevant for all cases.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
next prev parent reply other threads:[~2015-01-30 19:23 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-01-30 7:46 [PATCH 0/5] enhance configuring an ITS Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 7:46 ` [PATCH 1/5] irqchip: gicv3-its: allocate proper size for DT Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 19:10 ` Marc Zyngier
2015-01-30 19:10 ` Marc Zyngier
2015-01-31 1:57 ` Yun Wu (Abel)
2015-01-31 1:57 ` Yun Wu (Abel)
2015-01-30 7:46 ` [PATCH 2/5] irqchip: gicv3-its: zero itt before handling to hardware Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 19:24 ` Marc Zyngier
2015-01-30 19:24 ` Marc Zyngier
2015-01-30 7:46 ` [PATCH 3/5] irqchip: gicv3-its: use 64KB page as default granule Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 19:18 ` Marc Zyngier
2015-01-30 19:18 ` Marc Zyngier
2015-01-31 1:33 ` Yun Wu (Abel)
2015-01-31 1:33 ` Yun Wu (Abel)
2015-01-30 7:46 ` [PATCH 4/5] irqchip: gicv3-its: define macros for GITS_CTLR fields Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 7:46 ` [PATCH 5/5] irqchip: gicv3-its: add support for power down Yun Wu
2015-01-30 7:46 ` Yun Wu
2015-01-30 19:23 ` Marc Zyngier [this message]
2015-01-30 19:23 ` Marc Zyngier
2015-01-31 1:43 ` Yun Wu (Abel)
2015-01-31 1:43 ` Yun Wu (Abel)
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