Subject: Re: [PATCH] missing pci_disable_device()
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
Cc: greg@kroah.com, akpm@osdl.org, bjorn.helgaas@hp.com,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
In-Reply-To: <413D0E4E.1000200@jp.fujitsu.com>
References: <413D0E4E.1000200@jp.fujitsu.com>
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Date: Tue, 07 Sep 2004 10:49:45 +0100
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On Maw, 2004-09-07 at 02:26, Kenji Kaneshige wrote:
> Hi,
> 
> As mentioned in Documentaion/pci.txt, pci device driver should call
> pci_disable_device() to deallocate any IRQ resources, disable PCI
> bus-mastering and etc. when it decides to stop using the device.
> But there seems to be many drivers that don't use pci_disable_device()
> properly so far.

Think about unloading frame buffers or PCI devices with multiple
functions and multiple drivers. I agree the drivers definitely want
fixing where appropriate. I'm not sure your approach is safe (although a
debug printk would work wonders perhaps ?)

Another question: When I suggested doing exactly this for kexec I got
flamed by people claiming that disabling bus mastering isnt a defined
operation only enabling it. I'm still unconvinced by their protestations
but wonder what the PCI gurus can answer here.


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