On 11/17/2014 06:42 PM, Bjorn Helgaas wrote: > 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? Sorry for the lower-case typing. I broke my elbow and am down to one hand. bjorn, yep sounds reasonable. i'll do this (slowly unfortunately because of my arm) ... P. > > 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 > -- 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
