Re: USB problem on AT91RM9200-EK

[Matthias Kaehlcke <matthias@xxxxxxxxxxxx>]

El Tue, Nov 11, 2008 at 11:13:36PM -0800 armlinux@xxxxxxxxxx ha dit:

> I have a root file system on a regular USB-stick. When I am doing heavy file I/O
> the kernel reports:
> 
> usb 1-1: reset full speed USB device using at91_ohci and address 2
> usb 1-1: reset full speed USB device using at91_ohci and address 2
> usb 1-1: reset full speed USB device using at91_ohci and address 2
> sd 0:0:0:0: [sda] Result: hostbyte=0x07 driverbyte=0x00
> end_request: I/O error, dev sda, sector 1349096
> usb 1-1: reset full speed USB device using at91_ohci and address 2
> 
> The kernel version is:
> 
> Linux version 2.6.27 (e96dkn@gringo) (gcc version 4.2.4) #17 PREEMPT Tue Nov 11
> 13:38:24 CET 2008
> 
> CPU: ARM920T [41129200] revision 0 (ARMv4T), cr=c0007177
> 
> Machine: Atmel AT91RM9200-EK
> 
> 
> And I have tried different kernel versions with the same result. The severity of
> the problem changes with different brands on the thumb drive. Some brands bails
> out completely and the kernel remounts the disk as read only.
> 
> Has anyone seen something similar or have suggestions on how to proceed?

i ran into a similar experience on an ep93xx platform. in my case
adjusting the /sys/block/<device>/device/max_sector value
(http://www.linux-usb.org/FAQ.html#i5) significantly reduced the
number of resets, though they still occur ocasionally. there doesn't
seem to be a value that fits all devices, i found 32 working best on
my setup.

in the following thread people discuss several options to mitigate
the problem on their (x86) systems:

https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.22/+bug/61235

-- 
Matthias Kaehlcke
Embedded Linux Engineer
Barcelona

          Dreams and reality are opposites. Action synthesizes them
                             (Assata Shakur)
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
                                                                `. `'`
gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4                  `-

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