I have cubieboard2 nand chinese usb-modbus stik with ch340 chip.
when  I connet ch340 chip to usb cubieboard is freezed, ttyS0 is blocked.  cubieboard is work but is very very slow, ssh is not disconnected but don't answer by my command.
when I disconnect ch340 chip cubieboard will bee unfrozen but ttyS0 is blocked until I don't make hard (power) reset. Software reset is not unfroze ttyS0.

 

I cannot found src for ch340 chip diver. Driver from china web  is not compiling.

 

uname -a

Linux cubieboard2 4.14.18-sunxi #31 SMP Fri Feb 9 11:11:15 CET 2018 armv7l GNU/Linux

dmesg

 

[ 1129.203974] usb 4-1: new full-speed USB device number 4 using ohci-platform
[ 1129.478105] usb 4-1: New USB device found, idVendor=1a86, idProduct=7523
[ 1129.478120] usb 4-1: New USB device strings: Mfr=0, Product=2, SerialNumber=0
[ 1129.478126] usb 4-1: Product: USB2.0-Serial
[ 1129.480407] ch341 4-1:1.0: ch341-uart converter detected
[ 1129.493385] usb 4-1: ch341-uart converter now attached to ttyUSB0
[ 1210.401005] usb 4-1: USB disconnect, device number 4
[ 1210.402338] ch341-uart ttyUSB0: ch341-uart converter now disconnected from ttyUSB0
[ 1210.402462] ch341 4-1:1.0: device disconnected

 

lsmod

odule                  Size  Used by
cfg80211              376832  0
rfkill                 20480  2 cfg80211
sun4i_gpadc_iio        16384  0
8188eu                589824  0
sun4i_ts               16384  0
sun4i_codec            32768  3
ch341                  16384  0
snd_soc_core          118784  1 sun4i_codec
usbserial              24576  1 ch341
ir_lirc_codec          16384  0
evdev                  20480  1
lirc_dev               16384  1 ir_lirc_codec
snd_pcm_dmaengine      16384  1 snd_soc_core
snd_pcm                65536  2 snd_pcm_dmaengine,snd_soc_core
snd_timer              24576  1 snd_pcm
snd                    45056  3 snd_timer,snd_soc_core,snd_pcm
soundcore              16384  1 snd
sun4i_gpadc            16384  0
nvmem_sunxi_sid        16384  0
sunxi_cir              16384  0
sun4i_ss               24576  0
uio_pdrv_genirq        16384  0
uio                    16384  1 uio_pdrv_genirq
bonding                94208  0
fuse                   73728  1

Any help or suggestion?

Thanks,

Vlad

Work driver is here https://github.com/SkyRocknRoll/CH341SER_LINUX 

Thanks the all.