Ubuntu – Ubuntu 14.04 – USB serial port – device reports readiness to read but returned no data (device disconnected?)

14.04pythonusb

After two days of web searching I have to admit that this is beyond me and need some assistance please

I admin several machines(but do not claim to be a Linux admin), mainly running 12.04 LTS – we use a USB to serial adapter for a number of hookups in the lab.
One 12.04 process (for lack of a better word) was to chmod 777 /dev/ttyUSB0 so that the USB serial adapter can be installed or removed without the users having to do anything and this has worked well, if maybe not the correct way of doing this.
I updated one machine from 12.04 to 14.04 – and the update was seamless.
I had to replace another system, so we purchased a dell running windows 7 that I planned to make dual boot just like all the others.
Was unsuccessful ever loaded 14.04 – ended up loading 12.04 and then upgrading to 14.04 – very painful and exceeding long but finally got 14.04 up and running.
I am now hung on the USB serial issue – when installed I see it in /dev as ttyUSB0 and I have added the user to group so I can run it but always get the message when I run our python interface script:

device reports readiness to read but returned no data (device disconnected?)

Unfortunately our software developer isn't being helpful so I am hanging on limb here.

Lastly part of loading the python interface is to load two things
1 py.serial
2 google cmdline
Where I may have run off the road is loading these after upgrading to 14.04.
My current plan is to blow 14.04 away, reload 12.04 and get it all working from there – then try and update to 14.04 again.
Would very much apreichiate any assistance before taking that step
Thanks!!!!!

Best Answer

I had a similar Problem. After a recent update of ubuntu 14.04 my serial connections failed. I found this and it worked for me: https://bugs.launchpad.net/ubuntu/+source/python2.7/+bug/1501240

After booting the 3.13.0-63-generic kernel everything worked again.

btw: instead of chmod 777 every /dev/ttyUSB* you can maybe simply add the user to the group "dialout".

Related Solutions

Ubuntu – Send raw data to USB parallel port after upgrading to 11.10

The /dev/usb/lpX device files you are looking for are provided by the usblp driver. It seems in Ubuntu 11.10 though, that this driver has been blacklisted. See the /etc/modprobe.d/blacklist-cups-usblp.conf file:

# cups talks to the raw USB devices, so we need to blacklist usblp to avoid
# grabbing them
blacklist usblp

If you want to send data directly to the device still, you can temporarily load the driver with modprobe usblp (the blacklist only prevents the driver from being automatically loaded). Once you are done, you can unload it with modprobe -r usblp.

Ubuntu – Ubuntu Touch – USB serial drivers/modules

Thanks to ubuntu to get that functionality you will have to recompile the kernel. If you are still interested read bellow :)

All of usb serial adapters are by default disabled in any UT kernel. (thank you ubuntu for being so un-cool) [sarcasm on] as you are supposed to use this device only for socio* webapps (tweet, fazebook, stare to UT calendar) and do not dare to do anything cool [sarcasm off]. Look to the source of the kernel https://github.com/bq/aquaris-E4.5/tree/aquaris-E4.5/ change the configure file to enable your USB UART device and then crosscompile it (I think the best up to date instruction is this how to do that: https://sturmflut.github.io/ubuntu/bq/2015/07/02/hacking-the-bq-part-4-building-and-booting-a-kernel/) You should add the line for supporting your own USB UART device in the step 3 described in the above linked tutorial. To know the exact sting to write it is good to see mainline default kernel (3.4) tree, and add the appropriate line. Or look bellow....

The E.5 source tree is such a mess, and I could not find exact defconfigs for this device, however I am familiar with defconfigs of bq M10 (Caveat it is kernel 3.10 instead of 3.4 as on E4.5, some device drivers can be unavaliable in 3.4 tree), I provide the excerpt with it bellow. Find your device, and copy exact string to the 'project' configuration file mentioned in the link given before with instructions, uncomment and set it to 'y' at step 3 there:

#
# USB port drivers
#
CONFIG_USB_SERIAL=y
# CONFIG_USB_SERIAL_CONSOLE is not set
# CONFIG_USB_SERIAL_GENERIC is not set
# CONFIG_USB_SERIAL_AIRCABLE is not set
# CONFIG_USB_SERIAL_ARK3116 is not set
# CONFIG_USB_SERIAL_BELKIN is not set
# CONFIG_USB_SERIAL_CH341 is not set
# CONFIG_USB_SERIAL_WHITEHEAT is not set
# CONFIG_USB_SERIAL_DIGI_ACCELEPORT is not set
# CONFIG_USB_SERIAL_CP210X is not set
# CONFIG_USB_SERIAL_CYPRESS_M8 is not set
# CONFIG_USB_SERIAL_EMPEG is not set
# CONFIG_USB_SERIAL_FTDI_SIO is not set
# CONFIG_USB_SERIAL_FUNSOFT is not set
# CONFIG_USB_SERIAL_VISOR is not set
# CONFIG_USB_SERIAL_IPAQ is not set
# CONFIG_USB_SERIAL_IR is not set
# CONFIG_USB_SERIAL_EDGEPORT is not set
# CONFIG_USB_SERIAL_EDGEPORT_TI is not set
# CONFIG_USB_SERIAL_F81232 is not set
# CONFIG_USB_SERIAL_GARMIN is not set
# CONFIG_USB_SERIAL_IPW is not set
# CONFIG_USB_SERIAL_IUU is not set
# CONFIG_USB_SERIAL_KEYSPAN_PDA is not set
# CONFIG_USB_SERIAL_KEYSPAN is not set
# CONFIG_USB_SERIAL_KLSI is not set
# CONFIG_USB_SERIAL_KOBIL_SCT is not set
# CONFIG_USB_SERIAL_MCT_U232 is not set
# CONFIG_USB_SERIAL_METRO is not set
# CONFIG_USB_SERIAL_MOS7720 is not set
# CONFIG_USB_SERIAL_MOS7840 is not set
# CONFIG_USB_SERIAL_MOTOROLA is not set
# CONFIG_USB_SERIAL_NAVMAN is not set
# CONFIG_USB_SERIAL_PL2303 is not set
# CONFIG_USB_SERIAL_OTI6858 is not set
# CONFIG_USB_SERIAL_QCAUX is not set
# CONFIG_USB_SERIAL_QUALCOMM is not set
# CONFIG_USB_SERIAL_SPCP8X5 is not set
# CONFIG_USB_SERIAL_HP4X is not set
# CONFIG_USB_SERIAL_SAFE is not set
# CONFIG_USB_SERIAL_SIEMENS_MPI is not set
# CONFIG_USB_SERIAL_SIERRAWIRELESS is not set
# CONFIG_USB_SERIAL_SYMBOL is not set
# CONFIG_USB_SERIAL_TI is not set
# CONFIG_USB_SERIAL_CYBERJACK is not set
# CONFIG_USB_SERIAL_XIRCOM is not set
CONFIG_USB_SERIAL_WWAN=y
CONFIG_USB_SERIAL_OPTION=y
# CONFIG_USB_SERIAL_OMNINET is not set
# CONFIG_USB_SERIAL_OPTICON is not set
# CONFIG_USB_SERIAL_VIVOPAY_SERIAL is not set
# CONFIG_USB_SERIAL_XSENS_MT is not set
# CONFIG_USB_SERIAL_ZIO is not set
# CONFIG_USB_SERIAL_WISHBONE is not set
# CONFIG_USB_SERIAL_ZTE is not set
# CONFIG_USB_SERIAL_SSU100 is not set
# CONFIG_USB_SERIAL_QT2 is not set
# CONFIG_USB_SERIAL_DEBUG is not set

Not crippled linux would work with only missing kernel module compiled.But in this android-like kernel I am very unsure it would work with module, at least I could not find any instructions showing how to do that on these mediatek-android devices.

It appears Ubuntu shaved a lot of goodies from kernel, probably trying to hide very huge RAM usage by unity. This default setup makes impossible to use the tablets/phones with UT for anything other than reading mails, tweeting, stairing to UT calendar and calculating 1+1. Nothing cool by default.

Best Answer

Related Solutions

Ubuntu – Send raw data to USB parallel port after upgrading to 11.10

Ubuntu – Ubuntu Touch – USB serial drivers/modules

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