I am much-troubled by my Sansa c150, and transfering MP3 files through Amarok

- I have libusb-devel and libmtp installed.
- On the device is an XML file "WMPInfo.xml" which bears a remarkable similarity to the line in /etc/udev/rules.d so a copied the relevant line (Sansa c150) and added it to the XML file and re-named that file to "Info.xml"
- The device will still synchronise with WMP on a Windows machine and all the files are readable and the device is writable under Windows,
- I have 4 folders (empty) when the player automounts but using the Media Transfer Protocol - nothing happens..... " unable to connecct to MTP device" says Amarok !

The music I have already stored on the device is invisible, the amount of available disc-space is roughly the amount that would be registered if it was completely empty

So perhaps the solution isn't to make the device more recognisable (the xml edit) but to change the rules that Fedora uses to open the MP3 player.

Also when connected I am unable to change the ownership/permissions of the mounted gadget
- it is always owned by root and is a member of the root group and is read-only Which is perhaps why it won't allow MP3 transfers - I suppose

So at the moment I'm unclear about
- the device not recognising fedora core 6
- fc6 not recognising the MP3 player

and

- how would one change permissions to allow users to read and write to the bothersome thing !

Ran mtp-detect with the device connected and the following was returned, --

$ mtp-detect
Found non-autodetected device "SanDisk Sansa c150" on USB bus...
usb_claim_interface(): Device or resource busy
Connection error.
No devices.


--Right, so Fedora can see the device but doesn't recognise it.

I don't know what it's busy doing but it's not being read, nor is it reading.

This isn't encouraging

I still don't know whether the issue is with Fedora or the MP3 player

<libmtp>=/dev/libmtp*
<console> 0600 <libmtp> 0600 root

libmtp permissions seem to lock the device to root

should more lines be added
or this line edited ?

Maybe it's another line in fstab I should be considering

/dev/sda1/mnt/Sansa_c150 vfat something something something


what should the somethings be replaced with ?

I think were getting a little ahead of ourselves. I will say that I've had many usb problems and I didn't get all of them working. The place I would start is that you have files on there you can't see. But on top of that you can see the folders. Those two things aren't sitting right with me.

--You plug it in
--It Mounts
--Folder opens to show other folders
--No music

Is that about right? After you plug it in do

# dmesg | tail

and lets start with that.

nomb

$ dmesg| tail
sda: Mode Sense: 37 00 00 08
sda: assuming drive cache: write through
SCSI device sda: 3913440 512-byte hdwr sectors (2004 MB)
sda: Write Protect is off
sda: Mode Sense: 37 00 00 08
sda: assuming drive cache: write through
sda: sda1
sd 0:0:0:0: Attached scsi removable disk sda
usb-storage: device scan complete
sd 0:0:0:0: Attached scsi generic sg0 type 0


ran as a user (nothing 'super' about me)

yes, I can see folders (and I have music on the device-only about 600Mb free). The folders are empty.
So whatever is already on there can't be seen but disconnected from the PC the files already loaded play as well as could be expected

it isn't a USB problem though.

It's an MTP issue.

Had I not loaded the player up with 250+ MP3 tracks using a Windows machine before connecting to FC6 I would have opted for the 'don't handle' plug-in and MSC transfer settings in Amarok and the device.

The device behaves as a USB drive as well as any other USB flash-drive

It's a matter of negotiating an MTP relationship so I can see the already-installed files, the remaining capacity and download items from my Amarok collection.

How does libmtp match the device to the protocol ?

I mean, there's an XML file (WMPInfo) that has some device id which in no way, shape or form resembles the entry in libmtp.rules

or is it embedded in the (invisible) firmware ?

I don't know if this will expedite any resolution of this vexing matter but the previously mentioned file says

<DeviceInfo>
<WMPDeviceID = "{C77D97D5-6118-4DDA-928D-A81DF4B2E452}"RelationshipID"{00000000-0000-0000-0000-000000000000}"/>

this information has been provided by 'usbutils'

Bus 005 Device 005: ID 0781:7410 SanDisk Corp.

I was able to successfully connect to my Sansa c150.

The problem is udev configures the usb-storage and prevents libmtp from accessing the device.

As root,
(1) unload usb-storage

rmmod usb-storage

(2) temporarily move usb-storage.ko out of the way

cd /lib/modules/2.6.X/kernel/drivers/usb/storage
mv usb-storage.ko usb-storage.tmp

(3) plug-in your Sansa c150

You will now be able to use mtp commands to access the
mtp-only files.