Linux/Jádro/Chyby/ehci hcd/diary/2008-04-14.Mon

Datum: 2008-04-14.Mon

Diářový záznam, týkající se projevů chybného modulu ehci_hcd ještě nemuselo výt zjevné, že se jedná o tento modul)

@INA:


https://bugs.launchpad.net/ubuntu/+source/linux-source-2.6.22/+bug/88746

Bug #88746 (ehci-hcd), first reported on 2007-02-28 by  Al Buntu 
ehci_hcd module causes I/O errors in USB 2.0 devices

Bug description 
Tags: ehci-hcd qa-hardy-list usb 

Certain USB devices do not work properly, or do not work at all, while the ehci_hcd module is loaded.

A solution is to unload the ehci_hcd module, which is loaded every time the computer starts, using the command 'sudo modprobe -r ehci_hcd'. This works fine but unfortunatly ehci-hcd is necessary for using USB 2.0, so you lose USB 2.0 features.
Another solution is to disable USB 2.0 through the BIOS setup.

With some devices it is possible to read files normally (ie. copy files from an USB pendrive to the computer), but the device disconnects abrubtly when you start writing data on the device. In some devices it fails after writing a certain amount of data, probably the size of the write cache.

Steps to reproduce:
1. Insert your USB 2.0 device (like a flash drive)
2. If the device is recognised and mounted properly try copying a file to it.
3. Comfirm with the 'dmesg' command that it isn't functioning properly. (I/O errors etc)
4. Remove the USB device
5. Unload ehci_hcd with 'sudo modprobe -r ehci_hcd'
6. Insert your USB device again.
7. Check that everything works. (copy some files, etc.)

$ uname -a
Linux ina 2.6.22-3-k7 #1 SMP Mon Nov 12 09:12:50 UTC 2007 i686 GNU/Linux

# modprobe -r -v ehci_hcd

ina:/home/petr/psion# date; badblocks -o emtec.badblocks.usb1.all -v -w /dev/sdb; date
Mon Apr 14 23:59:07 CEST 2008
Hledám špatné bloky v režimu čtení i zápis
Od bloku 0 do 1970136
Zkouším se vzorkem 0xaa: hotovo                                
Čtu a porovnávám: hotovo                                
Zkouším se vzorkem 0x55: hotovo                                
Čtu a porovnávám: hotovo                                
Zkouším se vzorkem 0xff: hotovo                                
Čtu a porovnávám: hotovo                                
Zkouším se vzorkem 0x00: hotovo                                
Čtu a porovnávám: hotovo                                
Průchod dokončen, nalezeno 0 špatných bloků.
Tue Apr 15 04:38:56 CEST 2008


4:38:56+0:0:53=4:39:49=16789s

((4*60+39)*60)+49

1970136/16789=117 blks/s = 117 kB/s read+write = cca 234 kB/s + něco