[+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 <[email protected]>
> Cc: [email protected]
> Signed-off-by: Prarit Bhargava <[email protected]>
> ---
> 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.
Bjorn
> return 0;
> }
> early_param("pci", pci_setup);
> --
> 1.7.9.3
>
> --
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On Mon, Nov 10, 2014 at 8:59 PM, Bjorn Helgaas <[email protected]> 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 <[email protected]>
>> Cc: [email protected]
>> Signed-off-by: Prarit Bhargava <[email protected]>
>> ---
>> 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
On 11/17/2014 06:42 PM, Bjorn Helgaas wrote:
> On Mon, Nov 10, 2014 at 8:59 PM, Bjorn Helgaas <[email protected]> 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 <[email protected]>
>>> Cc: [email protected]
>>> Signed-off-by: Prarit Bhargava <[email protected]>
>>> ---
>>> 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 [email protected]
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>
On Tue, Nov 18, 2014 at 5:42 AM, Prarit Bhargava <[email protected]> wrote:
> 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) ...
Ouch, sorry to hear that. We need to get working on that direct
mind-computer interface :) Hope your elbow heals well!
Bjorn