Re: [RFC] [PATCH] PNP: request ioport and iomem resources used byactive devices

From: Maciej W. Rozycki
Date: Mon Nov 12 2007 - 12:06:55 EST


On Wed, 7 Nov 2007, Bjorn Helgaas wrote:

> There will undoubtedly be errors in what the firmware reports. But if
> firmware tells us about some non PC/AT device, we should believe it at
> least enough to avoid placing some other device on top of it.
>
> If we have PNPBIOS or ACPI, the built-in stuff reserved in
> request_standard_resources() should be superfluous. In theory.
> But I doubt there's any benefit in skipping request_standard_resources().
> Possibly it could be done *after* the PNP reservations, so the
> hierarchy would make more sense, but I don't know if even that
> is worth the trouble.

In practice it is resources above 0x00ff that really matter here as using
the motherboard range for device allocation is unsafe anyway (the whole
range may be actively decoded by the south bridge). So whatever is
reported between 0x0000 and 0x00ff is mostly informational; with some
protection against driver bugs perhaps (that assuming they have got error
handling right for reservations). I second it is not worth the hassle.

Maciej
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