Re: [linux-usb-devel] [PATCH] USB: consolidate error values fromEHCI, UHCI and OHCI _suspend()

From: Jiri Kosina
Date: Tue Sep 19 2006 - 06:46:02 EST


On Mon, 18 Sep 2006, David Brownell wrote:

> > EHCI, UHCI and OHCI USB host drivers are not consistent when returining
> > error values from their _suspend() functions, in case that the device is
> > not in suspended state. This could confuse users, so let all three of them
> > return -EBUSY.
> Shouldn't you also update uhci_suspend()? Currently it just ignores
> hcd->state ...

You are right that the patch is possibly not fully correct. I was trying
to fix the situation I was getting into with the bug in usb_resume_both()
(see my "[PATCH] 2.6.18-rc6-mm2 - usb_resume_both() - fix suspend/resume"
mail from yesterday), but now it is obvious that the EINVAL from UHCI is
of a "different kind" than EBUSY from OHCI and UHCI (though they are
triggered in the same situations -- when the previous resume was not done
correctly).

As far as I can see, the UHCI driver is, strangely enough, not using
hcd->state at all.

(by the way, EHCI and OHCI seem to have broken (read: missing) locking
when accessing the hcd->state. Should I fix it by per-hcd spinlock, or
does the patch already exist somewhere?)

Thanks,

--
Jiri Kosina
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