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SubjectRe: avoiding pci_disable_device()...
Takashi Iwai wrote:
> At Mon, 14 Feb 2005 11:34:13 -0800,
> Greg KH wrote:
>
>>On Mon, Feb 14, 2005 at 08:24:29PM +0100, Takashi Iwai wrote:
>>
>>>At Mon, 14 Feb 2005 11:06:19 -0800,
>>>Greg KH wrote:
>>>
>>>>>As a result, I have committed the attached patch to libata-2.6. In many
>>>>>cases, it is a "semantic fix", addressing the case
>>>>>
>>>>> * pci_request_regions() indicates hardware is in use
>>>>> * we rudely disable the in-use hardware
>>>>>
>>>>>that would not occur in practice.
>>>>>
>>>>>But better safe than sorry. Code cuts cut-n-pasted all over the place.
>>>>>
>>>>>I'm hoping one or two things will happen now:
>>>>>* janitors fix up the other PCI drivers along these lines
>>>>>* improve the PCI API so that pci_request_regions() is axiomatic
>>>>
>>>>Do you have any suggestions for how to do this?
>>>
>>>How about to add an exclusiveness check in pci_enable_device()?
>>>Most drivers suppose that the given pci resources are exclusively
>>>available.
>>
>>You mean only allow pci_enable_device() to work for the first caller of
>>it? I don't see how that would help this issue out.
>
>
> Well, for example, add a new pointer to indicate the driver accessing
> exclusively. And pci_enable_device() (maybe a new variant would be
> better for compatibility) checks whether this is free.
>
> The second caller wouldn't reach even to pci_request_regions() because
> of this check. So, no side-effect of pci_disable_device() in the
> error path.

This doesn't work with a driver that is properly using
request_resource(), but not using the PCI API.

Jeff



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