From: Alan Stern <stern@rowland.harvard.edu>
To: Michael Tessier <michael.tessier@axiontech.ca>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>
Subject: RE: PROBLEM: USB isochronous urb leak on EHCI driver
Date: Tue, 6 Jan 2015 11:48:01 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1501061144320.1602-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <66A26A9AA227D947AF088537F041526E2009B9@VSVR-EX10-MB1.pocatec.com>
On Tue, 6 Jan 2015, Michael Tessier wrote:
> > > That is interresting, however, I have an older kernel running an OHCI
> > > driver which is able to handle 4 codecs. Same usb hardware (codecs and
> > > hub), but older kernel on a different CPU, with much less power. This
> > > makes me believe that there's a solution to make it work...
> >
> > Of course there is: Install an OHCI host controller and use it to drive your codecs. It should work fine.
> >
> > The periodic scheduling algorithm for OHCI is very different from the algorithm for EHCI.
>
> According to your knowledge, how much time would you think it takes to
> change the EHCI driver with an OHCI one?
I don't understand the question.
> And can you tell if the OHCI driver
> will work on my hardware given that the Host controller of the i.MX512 is
> a USB2.0 host controller? (OHCI was implemented for USB 1.x from what I
> understand)
The OHCI driver works with OHCI hardware and the EHCI driver works with
EHCI hardware. OHCI is USB-1.1 and EHCI is USB-2. They are not
interchangeable.
> I tried to do so several days ago with the built-in configurator
> (I am using "ltib"), but the configurator does not allow selecting the
> OHCI driver; I tried manually but it turned into compiler errors...
It looks like the configurator is smart; it won't let you select the
wrong driver for your hardware.
Alan Stern
next prev parent reply other threads:[~2015-01-06 16:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-12-15 20:53 PROBLEM: USB isochronous urb leak on EHCI driver Michael Tessier
2014-12-15 21:48 ` Greg KH
2014-12-15 23:13 ` Fabio Estevam
2014-12-17 2:21 ` Peter Chen
2014-12-17 14:06 ` Michael Tessier
2014-12-17 16:40 ` Alan Stern
2015-01-05 15:12 ` Michael Tessier
2015-01-05 16:00 ` Alan Stern
2015-01-06 16:40 ` Michael Tessier
2015-01-06 16:48 ` Alan Stern [this message]
2015-01-06 17:38 ` Michael Tessier
2015-01-06 18:22 ` Alan Stern
2015-01-09 7:20 ` Peter Chen
2015-02-09 23:21 ` Michael Tessier
2015-02-10 2:09 ` Alan Stern
2015-02-10 15:11 ` Michael Tessier
2015-02-10 16:01 ` Alan Stern
2015-01-05 17:28 ` Fabio Estevam
2015-01-06 16:50 ` Michael Tessier
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