Re: [PATCH] PCI: Add pci shutdown ability

From: Alan Stern (stern_at_rowland.harvard.edu)
Date: 05/11/05

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    Date:	Wed, 11 May 2005 10:38:16 -0400 (EDT)
To: Vivek Goyal <vgoyal@in.ibm.com>

    On Wed, 11 May 2005, Vivek Goyal wrote:

    > > I looked into the possibility of having the PCI core disable interrupt
    > > generation and DMA on each new device as it is discovered. Unfortunately
    > > there is no dependable, universal way to do this for IRQs. (A notable gap
    > > in the original PCI specification, IMHO.)
    >
    > PCI specification 2.3 onwards, command register bit 10 can be used for
    > disabling the interrupts from respective device. And the very reason for
    > introducing this bit seems to be to not allow the device issue interrupts
    > until a suitable driver for the device has been loaded. Have a look at
    > following message.
    >
    > http://www.pcisig.com/reflector/msg05302.html
    >
    > Probably this feature can be used to disable the interrupts from the devices
    > and enable these back when respective driver is loaded. This will resolve
    > the problem of drivers not getting initialized in second kernel due to shared
    > interrupts in kdump and reliability of capturing dump can be increased.

    That's good, and it's certainly a step in the right direction. It won't
    help with any pre-PCI-2.3 devices out there but it might be worth trying
    to implement.

    Alan Stern

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