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From: jeffy <jeffy.chen@rock-chips.com>
To: Shawn Lin <shawn.lin@rock-chips.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Marc Zyngier <marc.zyngier@arm.com>,
	Thomas Gleixner <tglx@linutronix.de>
Cc: Heiko Stuebner <heiko@sntech.de>,
	linux-pci@vger.kernel.org, linux-rockchip@lists.infradead.org,
	linux-kernel@vger.kernel.org,
	Douglas Anderson <dianders@chromium.org>,
	Brian Norris <briannorris@chromium.org>
Subject: Re: [RFC PATCH] PCI: rockchip: fix system hang up if activate CONFIG_DEBUG_SHIRQ
Date: Thu, 10 Aug 2017 16:39:59 +0800	[thread overview]
Message-ID: <598C1BDF.6010203@rock-chips.com> (raw)
In-Reply-To: <1502353273-123788-1-git-send-email-shawn.lin@rock-chips.com>

Hi shawn,

On 08/10/2017 04:21 PM, Shawn Lin wrote:
> With CONFIG_DEBUG_SHIRQ enabled, the irq tear down routine
> would still access the irq handler registed as a shard irq.
> Per the comment within the function of __free_irq, it says
> "It's a shared IRQ -- the driver ought to be prepared for
> an IRQ event to happen even now it's being freed". However
> when failing to probe the driver, it may disable the clock
> for accessing the register and the following check for shared
> irq state would call the irq handler which accesses the register
> w/o the clk enabled. That will hang the system forever.

i think this extra irq call is to make sure it's safe to get a shared 
irq when we are freeing it, and we would not get this irq after freed it.

so maybe just call devm_free_irq before disable clks(and other required 
resources for the irq handler)? and also do it in the rockchip_pcie_remove.

WARNING: multiple messages have this Message-ID (diff)
From: jeffy <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
To: Shawn Lin <shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
	Bjorn Helgaas <bhelgaas-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>,
	Marc Zyngier <marc.zyngier-5wv7dgnIgG8@public.gmane.org>,
	Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>
Cc: Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>,
	linux-pci-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	Brian Norris
	<briannorris-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	Douglas Anderson
	<dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org>,
	linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
	linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [RFC PATCH] PCI: rockchip: fix system hang up if activate CONFIG_DEBUG_SHIRQ
Date: Thu, 10 Aug 2017 16:39:59 +0800	[thread overview]
Message-ID: <598C1BDF.6010203@rock-chips.com> (raw)
In-Reply-To: <1502353273-123788-1-git-send-email-shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org>

Hi shawn,

On 08/10/2017 04:21 PM, Shawn Lin wrote:
> With CONFIG_DEBUG_SHIRQ enabled, the irq tear down routine
> would still access the irq handler registed as a shard irq.
> Per the comment within the function of __free_irq, it says
> "It's a shared IRQ -- the driver ought to be prepared for
> an IRQ event to happen even now it's being freed". However
> when failing to probe the driver, it may disable the clock
> for accessing the register and the following check for shared
> irq state would call the irq handler which accesses the register
> w/o the clk enabled. That will hang the system forever.

i think this extra irq call is to make sure it's safe to get a shared 
irq when we are freeing it, and we would not get this irq after freed it.

so maybe just call devm_free_irq before disable clks(and other required 
resources for the irq handler)? and also do it in the rockchip_pcie_remove.

  reply	other threads:[~2017-08-10  8:40 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-10  8:21 [RFC PATCH] PCI: rockchip: fix system hang up if activate CONFIG_DEBUG_SHIRQ Shawn Lin
2017-08-10  8:39 ` jeffy [this message]
2017-08-10  8:39   ` jeffy
2017-08-10  9:14   ` Shawn Lin
2017-08-10  9:25     ` jeffy
2017-08-10  9:27 ` Heiko Stuebner
2017-08-10  9:40   ` jeffy
2017-08-10 11:04   ` Shawn Lin

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