Re: [PATCH 02/10] xhci: 'noxhci_port_switch' kernel parameter

From: Dan Williams
Date: Wed May 21 2014 - 02:21:12 EST


On Tue, May 20, 2014 at 5:27 PM, Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>> Greg,
>>
>> Sorry, I don't think it is fair to users to force them to re-compile
>> their kernel to get their device to work.
>
> I totally agree.
>
>> Granted, I'm new to USB
>> development, but the rate of reports of endpoint devices that mess up
>> and require quirks in the hcd-driver or usb-core seems un-ending to
>> me. So, I don't think it is fair to expect that the tide of quirky
>> devices will be stemmed in any reasonable amount of time. Having a
>> "works with noxhci_port_switch" report from users is good data (hmm, I
>> think a printk to tell users to file a report upstream if the option
>> resolves their issue is needed).
>
> How about just adding a debugfs file instead? That way, once you fix
> this, we can then remove it and no one will care.

The only thing stopping me from saying "deal." is that this darn
things is presently a pci quirk. So it happens well before the user
has a chance to manually override it with a debugfs file.

Let me look into delaying the quirk until the driver loads, because
ideally the right interface for this is "blacklist xhci_hcd" in
/etc/modprobe.conf.
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