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Resetting the touch screen on VU7+

Posted: Fri Nov 16, 2018 4:51 am
by Sebas_Ledesma
Hi:

I'm using Ubuntu 18.04 + kernel 3.16.60-28.
Sometimes when i reboot my device the touch on the VU7+ does not work, in this condition rebooting sometimes solves the problem (not always).
There is a way to unmount and re-mount the device via command line?

Thanks in advance.

Sebas

Re: Resetting the touch screen on VU7+

Posted: Fri Nov 16, 2018 7:34 am
by rooted
Rmmod and modprobe the driver is the only other way I know of.

Re: Resetting the touch screen on VU7+

Posted: Fri Nov 16, 2018 9:51 am
by odroid
If the boot/reboot process causes a short period of voltage drop due to heavy load, the touchscreen controller couldn't detect properly.
In that case, you have to connect a separated power supply to the Vu7+ with a power bridge board.
https://www.hardkernel.com/shop/micro-u ... dge-board/

Check "lsusb" output to find "16B4:0705" touch controller ID.

Or, turning off and on the USB Host ports with the sysfs gpio interface:

Code: Select all

echo 126 > /sys/class/gpio/export
echo out > /sys/class/gpio/gpio126/direction
echo 0 > /sys/class/gpio/gpio126/value       # OFF
echo 1 > /sys/class/gpio/gpio126/value       # ON

Re: Resetting the touch screen on VU7+

Posted: Thu Nov 22, 2018 4:10 am
by Sebas_Ledesma
lsusb shows that 16B4:0705 device is in the system.
Bus 001 Device 003: ID 16b4:0705 iStation
I've tried with:
echo 126 > /sys/class/gpio/export
but I get 'Permission denied' (Using Ubuntu 18.04 with Kernel 3.16.60-28).
I've tried also with 'sudo echo...' with the same result.


Sebas

Re: Resetting the touch screen on VU7+

Posted: Thu Nov 22, 2018 9:33 am
by odroid
Run the commands after issuing "sudo su".

Re: Resetting the touch screen on VU7+

Posted: Sat Aug 24, 2019 5:06 am
by Sebas_Ledesma
Hi:

I've found a way to do it.
I've used usbreset from Alan Stern available here:
https://marc.info/?l=linux-usb&m=121459435621262&w=2

I use lsusb to detect the bus where the device it's connected, then I call usbreset and the device starts to work.

Sebas