From: Matthias Fuchs <matthias.fuchs@esd•eu>
To: Alan Stern <stern@rowland•harvard.edu>
Cc: Greg KH <greg@kroah•com>,
linux-usb@vger•kernel.org, linuxppc-dev@ozlabs•org
Subject: Re: Problem with full speed devices on PowerPC MPC5121 host port
Date: Tue, 17 Jan 2012 15:12:50 +0100 [thread overview]
Message-ID: <4F1581E2.9030400@esd.eu> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1201061258040.1326-100000@iolanthe.rowland.org>
On 06.01.2012 19:03, Alan Stern wrote:
> On Fri, 6 Jan 2012, Matthias Fuchs wrote:
>
>> For my eyes it does not really look like a general USB issue.
>> It looks like a problem with the Freescale EHCI implementation that is
>> influenced by high interrupt or internal bus load caused by the flood ping.
>
> Indeed, it might be a problem with the built-in Transaction Translator.
> That would explain why it affect full-speed devices.
>
> However, I would expect the resetting the controller hardware (which
> happens when you reload the ehci-fsl driver) would fix any such issues.
> It's hard to imagine how a problem could survive a reset like that.
I did the tests again. When the error occured I reloaded the ehci-hcd driver and reconnected the device. It ends up with some kernel messages
that come up time after time:
usb 1-1: new full-speed USB device number 2 using fsl-ehci
usb 1-1: device descriptor read/64, error -110
usb 1-1: device descriptor read/64, error -110
usb 1-1: new full-speed USB device number 3 using fsl-ehci
usb 1-1: device descriptor read/64, error -110
usb 1-1: device descriptor read/64, error -110
usb 1-1: new full-speed USB device number 4 using fsl-ehci
usb 1-1: device not accepting address 4, error -110
usb 1-1: new full-speed USB device number 5 using fsl-ehci
usb 1-1: device not accepting address 5, error -110
hub 1-0:1.0: unable to enumerate USB device on port 1
A recommondation from freescale was to check the TXFILLTUNING register settings ("Initialization of this registers can produce problem if full-speed device is used").
So I tried various values in the TXFILLTUNING register (I added this
code to ehci_reset()). Finally I disabled USB streaming mode in the USBMODE register (set bit USBMODE_SDIS - btw., it should be defined as "1 << 4" in ehci_def.h at least for the MPC5121).
All this does not fix the problem or even have an impact.
This is my stripped down version of the test:
on the MPC5121 unit I do nothing but:
$~ stty -F /dev/ttyUSB0 -echo -crtscts -cstopb
$~ stty -F /dev/ttyUSB0 115200
$~ while true; do \
read LINE < /dev/ttyUSB0 \
echo $LINE > /dev/ttyUSB0 \
done
The other side looks like this:
$~ while true; do \
echo "_THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG 1234567890#" > /dev/ttyS0 \
done
and also I start a flood ping against the MPC5121 unit (.. to speed things up).
Can anybody with a MPC5121 board try to reproduce this?
Matthias
next prev parent reply other threads:[~2012-01-17 14:14 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <4EF3191D.9040508@esd.eu>
[not found] ` <20111222173900.GD28856@kroah.com>
2012-01-06 11:55 ` Problem with full speed devices on PowerPC MPC5121 host port Matthias Fuchs
2012-01-06 18:03 ` Alan Stern
2012-01-17 14:12 ` Matthias Fuchs [this message]
2012-01-18 11:08 ` Anatolij Gustschin
2012-01-18 13:42 ` Matthias Fuchs
2012-01-19 9:34 ` Anatolij Gustschin
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=4F1581E2.9030400@esd.eu \
--to=matthias.fuchs@esd$(echo .)eu \
--cc=greg@kroah$(echo .)com \
--cc=linux-usb@vger$(echo .)kernel.org \
--cc=linuxppc-dev@ozlabs$(echo .)org \
--cc=stern@rowland$(echo .)harvard.edu \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox