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Added kernel >= 4.4.52 workaround for low latency serial devices (SerialDV)

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f4exb 2017-05-05 09:29:50 +02:00
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@ -177,6 +177,12 @@ Although such serial devices work with a serial interface at 400 kb in practice
Note that this is not supported in Windows because of trouble with COM port support (contributors welcome!).
**Warning**
Since kernel 4.4.52 the default for FTDI devices (that is in the ftdi_sio kernel module) is not to set it as low latency. This results in the ThumbDV dongle not working anymore because its response is too slow to sustain the normal AMBE packets flow. The solution is to force low latency by changing the variable for your device (ex: /dev/ttyUSB0) as follows:
`echo 1 | sudo tee /sys/bus/usb-serial/devices/ttyUSB0/latency_timer`
Alternatively you can use [mbelib](https://github.com/szechyjs/mbelib) but mbelib comes with some copyright issues (see next). If you have mbelib installed in a custom location, say `/opt/install/mbelib` you will need to add these defines to the cmake command: `-DLIBMBE_INCLUDE_DIR=/opt/install/mbelib/include -DLIBMBE_LIBRARY=/opt/install/mbelib/lib/libmbe.so`
Possible copyright issues apart (see next) the audio quality with the DVSI AMBE chip is much better.