I have to push firmware files to multiple usb devices (2 files per device) via ymodem file transfer. However just before uploading the files the device needs to be rebooted to get access to the file transfer menu. Once it reboots the port that it gets assigned to is no longer the same - due to re-enumeration. As a result trying to open the port, that it was originally assigned to transfer the file gives an error. Is there a way around this or perhaps have a dedicated port for each device???
Thanks,
Archie
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I am trying to rename my audio device name. but it doesn't do anything when I rename it. it just simply close the setting. My setting for RDP is Local Resource-->play on this computer.
Its not possible to rename the audio device name on the VM as you are using remote audio driver from Microsoft to output the sound to your local machine . The driver name is bydefault remote audio.
We need to be able to change the mass storage function in a Linux composite USB gadget (to change the mounted directory). Currently the scripts teardown the UDC and restart it with the changed mount point.
The problem with this is that it disconnects the ACM device providing the command/control serial connection with a Windows PC.
Is there a way to just takedown/restart the mass storage portion of the composite device without stopping the entire UDC?
This is with kernel 4.1.9.
I need to detect when a USB serial device is plugged or unplugged on my embedded system and know what is the tty associated with it.
My system runs over a 2.6 Linux Kernel.
Since I don't have write access to udev rules, nowadays I'm trying to get this information from the file system, looking for modifications in /sys/bus/usb/devices directory. However, I'm facing some problems with this approach.
I know what is the Id BUS of the USB port connected (e.g 1-1.3). So, I search for the associated tty (looking for a directory in /sys/bus/usb/devices/<Id BUS>:1.0/tty/ - e.g. /sys/bus/usb/devices/1-1.3:1.0/tty/ttyACM0). This way I know that I should use /dev/ttyACM0 to communicate with my device.
But, sometimes, this device (/dev/ttyACM0) does not exist.
Is there any better way to get this information?
I even thought trying to get this information from the syslog, but I don't know whether this is a pretty good idea.
Edit:
Only to clarify, my system needs to be able to detect state changes in the USB bus, i.e. detecting when a new device is plugged (and getting the tty name linked to it) or an existing one is unplugged.
The system is monitoring up to N USB/serial devices, which are plugged to it using an USB HUB. During its normal execution new devices can be plugged, existing devices can be removed (or rebooted by a remote command - out of this scope). When a device is rebooted, it could receive a different tty from the previous one used before (e.g. ttyACM0 -> ttyACM3), since the kernel designates to it a tty which is free at the moment, and it is a big problem to me.
Netlink is the preferred mechanism for communication between kernel and userspace.
You would create a Netlink socket with family NETLINK_KOBJECT_UEVENT, listen on that socket and filter out messages that contain SUBSYSTEM=usb and ACTION=add for USB plug events or ACTION=remove for USB unplug events.
I wrote a USB abstraction library called libusbp. You should look at its port_name example, which shows how to use libusbp to get the serial port name (e.g. /dev/ttyACM0) for a USB serial device. Behind the scenes, libusbp gets this information using libudev.
Check if the virtual file is deleted using stat.
#include <sys/statvfs.h>
...
struct stat sb;
return (stat("/dev/ttyUSB0", &sb) == 0); // true if open, false otherwise
Is it possible to use the BB as Mass Storage Device?
I want it to be connected to an audio player that can read files from USB connectivity (such as USB flash drive) and act as data storage device containing one specific folder (and its sub-folders) from the file system (if possible, on a flash drive connected to the board.).
As the device specs says, it has connectivity of:
USB client for power & communications
USB host
Operating system will probably be Ubuntu but can be changed.
What drivers or configurations needs to be done in order to achieve this?
The latest images have already the mass storage usb gadget active, so a mass storage peripheral should be recognized by your system upon connection.
A quick google search reveals this discussion about a user trying to disable the USB MS gadget:
From the discussion, the files where the magic happens are:
Debian: /opt/scripts/boot/am335x_evm.sh
Ubuntu: /opt/scripts/boot/am335*
Armstrong: /usr/bin/g-ether-load.sh
In my Debian image the line you want to modify is:
modprobe g_multi file=${gadget_partition} cdrom=0 stall=0 removable=1 nofua=1 iSerialNumber=${SERIAL_NUMBER} iManufacturer=Circuitco iProduct=BeagleBone${BLACK} host_addr=${cpsw_1_mac}
and the corresponding $gadget_partition variable that is set just before that in order to customize the folder you want to expose.
Note that the g_multi gadget in its standard configuration presents 3 different devices: an ethernet interface, a mass storage peripheral and a serial interface. If you want to customize the parameters you can refer to the g_multi documentation (kernel.org)
I have a special bespoke device with a USB interface. When plugging in the device to my laptop - Ubuntu 12.04 it mounts as a read only USB drive - with a file on it. This file is created by the device and writes to the file when the device scans stuff.
I however, want to be able to write to the drive so the device 'thinks' it has already scanned x amount of entries.
Basically I want to replace the file 'File1.txt' my version of 'File1.txt' however I cannot because the drive is mounting as Read only.
I have tried the following commands:
andy#andy-ThinkPad-W530:/media/iRead$ touch giveme.txt
touch: cannot touch `giveme.txt': Read-only file system
andy#andy-ThinkPad-W530:/media/iRead$ sudo mount -o remount,rw '/media/iRead'
[sudo] password for andy:
mount: cannot remount block device /dev/sdb read-write, is write-protected
andy#andy-ThinkPad-W530:/media/iRead$
Can anybody suggest anything I can try to mount this as writable drive?
I have a very strong feeling that the chip which is storing this data is the following:
ARM STM32F103 RBT6 22oUP _ 93 MLT22950
Hope this helps somebody to help me!
If processing write commands coming from USB wasn't part of the requirements, it's very unlikely that the device processes write commands.
A read-only USB mass storage device is not a read-write mass storage device with write-protection slapped on top. It's a USB device that doesn't have logic for understanding write requests at all.
After the device is finished and delivered is a little late for deciding
I want to be able to write to the drive so the device 'thinks' it has already scanned x amount of entries.
Of course the flash memory used inside the device is written during its operation. But the way data is stored inside might not look anything like its USB presentation, and the conversion is most likely one-way only.
Since the developer probably did not implement mass storage support from scratch, and the library they used probably has write support, they may be able to easily supply you with firmware modified to be writable and do something with the written data. But without changing the firmware, you get nowhere.