Re: [Patch 1/1] x86 pci: Add option to not assign BAR's if not alreadyassigned

From: H. Peter Anvin
Date: Fri May 28 2010 - 16:05:28 EST


On 05/28/2010 10:10 AM, Mike Travis wrote:
>
>
> H. Peter Anvin wrote:
>> On 05/28/2010 09:53 AM, Mike Travis wrote:
>>> Any further consideration for this patch, or has it been rejected?
>>
>> Well, it's really up to Jesse, but as far as I can see, this patch is a
>> net loss of functionality and doesn't actually add anything. Without
>> this patch, some resources that were not assigned by BIOS will be
>> unreachable. With this patch, *all* resources that were not assigned by
>> BIOS will be unreachable...
>>
>> -hpa
>>
>
> Apparently you're missing the point of the patch? The patch is needed
> because BIOS is purposely not assigning I/O BAR's to devices that won't
> use them, freeing up the resource for devices that do need them. Where
> is the "all" resources that are not reachable?
>

No, the patch isn't needed for those.

Without your patch:

- Devices assigned by BIOS remain assigned;
- Devices not assigned by BIOS get assigned until address space
exhausted.

With your patch:

- Devices assigned by BIOS remain assigned;
- Devices not assigned by BIOS never get assigned at all.

What am I missing here?

-hpa

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