On Mon, Nov 10, 2014 at 8:59 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > [+cc lkml, linux-arch, Linus] > > On Sat, Nov 01, 2014 at 02:11:19PM -0400, Prarit Bhargava wrote: >> The kernel should boot PCI without the use of kernel parameters. Display >> a FW_BUG warning when pci= is used. >> >> Cc: Myron Stowe <mstowe@xxxxxxxxxx> >> Cc: linux-pci@xxxxxxxxxxxxxxx >> Signed-off-by: Prarit Bhargava <prarit@xxxxxxxxxx> >> --- >> drivers/pci/pci.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c >> index 625a4ac..5172060b 100644 >> --- a/drivers/pci/pci.c >> +++ b/drivers/pci/pci.c >> @@ -4515,6 +4515,8 @@ static int __init pci_setup(char *str) >> } >> str = k; >> } >> + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK); >> + pr_crit(FW_BUG "The PCI configuration has been overridden thorugh the use of pci=. Please report the issue you are attempting to resolve to your hardware vendor.\n"); > > My goal is to be able to boot without any "pci=" parameters, so from that > perspective, I like this. > > When people have a problem booting Linux, they often try a variety of > things like "pci=assign-busses", "pci=nocrs", "pci=nomsi", "pci=nommconf", > "pci=noacpi", etc. If they find something that works, there's a tendency > to treat that as a "solution." I'd rather that they report it, so we can > try to fix the bug or add a quirk so the *next* person won't have to figure > out the right parameters to use. > > My worry is that there are a few things where Linux isn't smart enough to > do the right thing automatically, and I don't think we'll have a good > solution in the near future. For example: > > pci=norom > pci=pcie_bus_perf,pcie_bus_safe,etc. > pci=cbiosize=... > pci=cbmemsize=... > pci=resource_alignment=... > pci=hpiosize=... > pci=hpmemsize=... > pci=realloc > > I don't like the fact that these options exist, but I suspect there are > users that do depend on them and might find this warning too aggressive. > > So I'm interested in opinions on whether this is a good idea at all and > whether we should exclude some options from the warning/tainting. Hi Prarit, We didn't get any nibbles :) I don't think we can realistically taint the kernel for *all* "pci=" options. So if you want to pursue this, maybe you could enhance this so we can have a whitelist of options that we will support without tainting. Then we can argue about what should be on the list and go from there. Does that seem reasonable? This is a somewhat more aggressive use of tainting than we've had in the past, so we might have to iterate on this a bit. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
