On Mon, Sep 23, 2013 at 12:15 AM, Alexey Neyman <sti...@att.net> wrote: > [Resending due to no response to the original message in a week] > > Hi all, > > I have a board with a BIOS bug that reports the following I/O port regions in > _CRS on one of the host bridges: > > 0x0000-0x03af // #0 > 0x03e0-0x0cf7 // #1 > 0x03b0-0x03bb // #2 > 0x03c0-0x03df // #3 > 0x0000-0xdfff // #4 > 0xf000-0xffff // #5 > > Obviously, region number #4 is erroneous as it overlaps with regions #0..3. > The code in coalesce_windows() in arch/x86/pci/acpi.c attempts to recover from > such kind of BIOS bugs by merging the overlapping regions. Current code > expands region #0 to 0x0000-0xdffff and makes region #4 ignored. As a result, > overlap of the expanded region #0 with regions #1..3 remains undetected (as > the inner loop already compared them with region #0). As a result, regions > #1..3 are inserted into the resource tree even though they overlap with > adjusted region #0 - which later results in resource conflicts for PCI devices > with IO ports in one of those regions (e.g., for an PCI IDE controller in > legacy mode - which has port 0x3f6). The kernel then refuses to initialize > these devices. > > The fix: instead of expanding res1 and ignoring res2, do the opposite. The > res2 window is yet to be compared against all windows between res1 and res2 > (regions #1..3 in the above example), so the resulting resource map will > include just the expanded region - and will ignore any overlapping ones. > > Signed-off-by: Alexey Neyman <sti...@att.net>
Can you please open a report at http://bugzilla.kernel.org, assign it to drivers/pci, and attach a complete dmesg log? Thanks, 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/
