usb mass media storage
shawnzier at gmail.com
shawnzier at gmail.com
Fri Sep 5 16:02:59 CEST 2008
On Fri, Sep 05, 2008 at 01:04:52PM +0200, pHilipp Zabel wrote:
> On Fri, Sep 5, 2008 at 4:41 AM, Dale Maggee <antisol at internode.on.net> wrote:
> > Petr Vanek wrote:
> >> I have spent a while googling this up and have no wiki skills but
> >> someone might find this useful:
> >> to make FR act as a memory stick, here is what my script does:
> >> #!/bin/sh
> >> /etc/init.d/networking stop
> >> rmmod g_ether
> >> modprobe g_file_storage file=/dev/mmcblk0p1
> >> --
> >> Petr Vaněk
> >> http://biodynamika.cz
> > very cool, but before I test it out (potentially breaking my usb
> > networking in the process), I have a couple of questions:
> > 1. will this persist over a reboot, or will it revert back to being an
> > ethernet gadget when I reboot?
> It's not persistent unless you add something like this to the init
> scripts. After rebooting the ethernet gadget will be back.
> > 2. is the following sufficient to switch it back?
> > #!/bin/sh
> > rmmod g_file_storage
> > modprobe g_ether
> > ifup usb0
> > (assuming I replaced '/etc/init.d/networking stop' with 'ifdown usb0' as
> > recommended by Daniel)
> > 3. can somebody point me to a resource for the g_file_storage module
> > where I can learn more about it? I did a couple of quick googles but
> > didn't see anything promising. specifically I'd like to know more about
> > the file parameter - I assume that in this scenario our "usb stick" is
> > using partition/device information from /dev/mmcblk0p1, and will be
> > partitioned in the same way as the SD card? what If I wanted to have my
> > home directory accessible in "usb stick" mode?
> I suggest to read the comment in the source code, it's quite detailed:
> The file parameter determines the raw backing store for the storage
> device, so if you
> have file=/dev/mmcblk0p1, its contents will directly appear as
> /dev/sdx on the host. As mmcblk0p1 doesn't contain a partition table,
> so won't sdx. If you want to export the whole device, use
> file=/dev/mmcblk0, you'll get the partition table in /dev/sdx and the
> kernel will parse it and create /dev/sdx1 (containing the contents of
> /dev/mmcblk0p1) etc.
> The host has direct access to the block device, so it is important
> that /dev/mmcblk0p1 is not mounted on both the phone and the host at
> the same time (unless it's mounted ro on both).
What if it was mounted ro on the phone side and rw on the host side? Would that cause problems?
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