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

[Dan Williams]

On Fri, May 23, 2014 at 11:39 PM, Holger Hans Peter Freyther
<holger@xxxxxxxxxxx> wrote:
> On Tue, May 20, 2014 at 03:40:16PM -0700, Dan Williams wrote:
>
> Dear Dan,
>
>> Sorry, I don't think it is fair to users to force them to re-compile
>> their kernel to get their device to work.  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
>
> thank you very much for this statement. xhci-hcd is unusable for
> many people. On my laptop I can't scan more than one document, the
> laptop sometimes immediately wakes up after suspend and after almost
> two years all of these issues remain.

That's sad.  We (Sarah, Mathias, and I) really want to fix that.

> I am running kernels with a hacked up pci-quirks.c for months and
> scanning documents work, suspend/resume is working, no issues with
> USB serials. My job is not related to Linux kernel development so
> I would love to go back to a distribution kernel. Please make this
> possible. In the end "xhci" appears to be a "supported" driver?

Yes, there are presently 3 people hacking on the xhci bug report
backlog at Intel where it was just a solitary hero before.  To be fair
I believe the rate of discovery of non-spec compliant quirkiness is to
blame.  In the meantime, as we ramp to get back on top of the tidal
wave of weird device interactions with xhci, I believe it is fair to
offer a workaround.

Let me see if I can achieve this with a debugfs interface so that
'noxhci_port_switch' does not become a permanent ABI per Greg's
concern.

--
Dan
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