On Wed, May 1, 2013 at 11:53 PM, Bin Gao <bin....@linux.intel.com> wrote: > On Wed, May 01, 2013 at 11:17:10AM -0600, Bjorn Helgaas wrote: >> Is there any possibility of multi-function devices at bus 0, device 0, 2, or >> 3? >> >> What about bridges -- can any of these be a bridge? >> >> If either of those could happen, these checks could be too specific. > 0:2:0 and 0:3:0 are the only 2 devices behind the bridge 0:0:0.
Please use the conventional Linux PCI address formatting (DDDD:BB:dd.f, where DDDD = domain (optional, often omitted if DDDD == 0), BB = bus, dd = device, f = function), because this is quite confusing. You say "0:2:0 and 0:3:0" are behind the bridge "0:0:0", but the patch you sent clearly applies only to devices on bus 0. The patch applies to devices 00:00.0, 00:02.0, and 00:03.0. These are all on the same bus, so none of them can be behind a bridge. If the 00:00.0 device is in fact a bridge, its secondary bus will be something other than 0, so any devices behind the bridge will be on a non-zero bus number. And I assume you would want to use config mechanism #1 to reach those devices, too. Your current patch doesn't do that -- it only applies to devices on bus 0. I dropped this patch until this gets straightened out. > These devices don't implement pcie capability list in legacy config space > so no offset above 255 would be triggered. > The fixed bar pcie capability located at 0x100 is for pci-shimed device > only, not for 0, 2 and 3. But current implementation applies it to 0, > 2 and 3 as well. This is what the patch is going to address. > >> >> Is there a doc that identifies these cases where config mechanism #1 >> should be used instead of MMCONFIG? > Unfortunately no doc identifies this. > But since FW doesn't provide pci shim for device 0, 2 and 3, > and these 3 real pci devices have only 256 bytes legacy pci > config space so they can only be accessed by type 1. > >> >> Bjorn >> -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
