LKML Archive on
help / color / mirror / Atom feed
From: David Brownell <>
To: Andrew Morton <>,
	"mahendra varman" <>
Subject: Re: usb detecting only high speed devices only - not detecting low speed devices
Date: Tue, 26 Feb 2008 18:17:02 -0800	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

On Tuesday 26 February 2008, Andrew Morton wrote:
> > usb 3-1: new low speed USB device using ohci_hcd and address 2
> > ohci_hcd 0000:01:04.1: Unlink after no-IRQ?  Controller is probably
> > using the wrong IRQ.

My diagnosis hasn't changed since last time he asked this question:
it's related to IRQ handling, outside the scope of USB.  If USB
were getting the OHCI interrupts, it would not issue that message.

Now as to *why* that happens, I don't know.  We've certainly had folk
using Philips/NXP EHCI controllers successfully before.  Maybe this
board has a hardware problem, like a bad chip or not having wired
up the power lines that OHCI controller uses.

One small experiment would be to try using ports that will hand
the device off to the *other* OHCI controller on that chip.  If
it's that kind of hardware issue, it might not apply to both of
the OHCI controllers.

  reply	other threads:[~2008-02-27  2:17 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-02-26 13:43 mahendra varman
2008-02-27  0:05 ` Andrew Morton
2008-02-27  2:17   ` David Brownell [this message]
2008-03-03  9:31     ` mahendra varman
2008-03-03 19:07       ` David Brownell

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \
    --subject='Re: usb detecting only high speed devices only - not detecting low speed devices' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).