Re: [PATCH] x86/pci: try to detect host_bridge pci_cfg_space

From: H. Peter Anvin
Date: Fri Mar 06 2009 - 20:05:26 EST


H. Peter Anvin wrote:
Yinghai Lu wrote:
Impact: get correct pci_cfg_size for host_bridge

more host bridges support 4k cfg, so check them directly
instead of quirks.

Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>

I'm utterly confused by this. This is basically saying we should try to probe for an extended device space for every host bridge. Logically speaking, this is valid: if there is a valid path by which we can probe for byte 256 then it should succeed.

HOWEVER, the same argument applies for *every single device*. So if this does indeed work, why should we limit it to host bridges?


Looking at the code (as opposed to just the patch) made it a bit clearer. The argument you're making here is that only host bridges are known to have extended address space without also having a PCI-X extension header, right?

-hpa

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