Messages in this thread | | | Date | Mon, 3 Sep 2007 11:17:18 +0200 | From | "Andreas Herrmann" <> | Subject | Re: [patches] [patch 3/5] x86: Add PCI extended config space access for AMD Barcelona |
| |
On Mon, Sep 03, 2007 at 01:31:57AM -0700, Arjan van de Ven wrote: > On Mon, 03 Sep 2007 10:17:39 +0200 > "Robert Richter" <robert.richter@amd.com> wrote: > > > This patch implements PCI extended configuration space access for > > AMD's Barcelona CPUs. It extends the method using CF8/CFC IO > > addresses. An x86 capability bit has been introduced that is set for > > CPUs supporting PCI extended config space accesses. > > > > > No offence but this feels a bit wrong to me. > > PCI is sort of more a chipset property than a cpu property (I realize > that this boundary is changing of course). > > I'd like to ask you to at least rename some of the feature bits to > indicate that the extended config space is for the IO access method; > after all Linux already supports the MMIO method for accessing extended > config space since a really long time; not marking the feature bit to > indicate it's the IO method is going to be extremely confusing and > cause bugs I bet.
Hmm, yes the naming of the CPU capability bit seems wrong. Guess, Robert will fix it.
> (we probably need a global function that drivers can use to find out of > extended config space is accessible; however that for sure isn't a CPU > capability bit.
IMHO this is already available. Just check pci_dev->cfg_size which is 256 if PCI ECS access is not possible (see pci_cfg_space_size()).
> However the current naming etc sort of makes me fear > drivers will abuse this thing while thinking it's the right API)
Do you see any other issues besides the naming of the bit?
Regards,
Andreas
-- Operating | AMD Saxony Limited Liability Company & Co. KG, System | Wilschdorfer Landstr. 101, 01109 Dresden, Germany Research | Register Court Dresden: HRA 4896, General Partner authorized Center | to represent: AMD Saxony LLC (Wilmington, Delaware, US) (OSRC) | General Manager of AMD Saxony LLC: Dr. Hans-R. Deppe, Thomas McCoy
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
| |