[Gta04-owner] Connecting USB-Stick

Sven openmoko at maricon.de
Mon Sep 17 22:14:18 CEST 2012


Hello Neil,

many thanks for your hint! Never I would have thought that an USB-stick 
wants to have so much power! Using the suggested USB hub and QtMoko v47 
I now get the following devices:

/dev/bsg
/dev/sda
/dev/sda1
/dev/usbdev2.2
/dev/usbdev2.3

Using QtMoko v48 I only get:

/dev/bsg
/dev/sda
/dev/sda1

Mounting /dev/sda1 works nicely and gives proper access to all data on 
the stick. Many thanks!


Another question:
Is the limitation to 100mA due to hardware or to software? Or in other 
words: Would it be possible that QtMoko throws a question directly after 
booting, something like: "You connected an USB device that requests 
200mA. Do you want to provide this with regard to your battery lifetime?"

Because it would not be very practical always to have an USB hub and an 
external battery with you if you intend to attach an USB stick while 
you're out of your home with your mobile phone...

Best regards
    Sven



On 17.09.2012 00:35, NeilBrown wrote:
> On Fri, 14 Sep 2012 12:44:30 +0200 Sven<openmoko at maricon.de>  wrote:
>
>> Hello,
>>
>> meanwhile I also could get some cables that provide an
>> USB-host-connector on the OTG-port of the gta04 by connecting the ID pin
>> to ground. If I connect an USB stick during poweroff and start booting
>> then, after some time the stick's LED will light, indicating that it
>> will really get power. Within a terminal session of QtMoko v47 I can do
>> "ls /dev" and see at least that a /dev/usbdev2.2 has occured that will
>> not be there without the USB stick connected. QtMoko v48 even doesn't do
>> that. There nothing will happen at all.
>>
>> When trying to mount /dev/usbdev2.2 under QtMoko v47, I always get the
>> error message "not a block device", although the stick contains a valid
>> FAT file system and mounting on another Linux system works without
>> problems. What's wrong here?
>>
>> Besides: When QtMoko v47 suspends, it also will switch off the power of
>> the USB device. I think it shouldn't do that. And especially after
>> resuming, it should at least switch it on again, what currently it
>> doesn't do. More suspicious behaves QtMoko v48: It tries to suspend, the
>> USB stick's LED flickers one short time, and then QtMoko v48 resumes at
>> once again. It needs several attemps of this suspending/resuming, until
>> it really suspends. Of course then also without switching on USB's power
>> again after resume...
>>
> I doubt that "/dev/usbdev2.2" is really the USB stick.  What does
>    ls -l /dev/usbdev2.2
> show?
>
> The OTG port in the GTA04 will only provide 100mA.  All USB sticks I've
> tried claim to require 200mA, so they don't get recognised at all.
> Maybe if you used a power-hub....
>
> NeilBrown



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