Hi David, I found a problem with the driver. In this situation, the SDA line is stuck low, but never clears, until cold rebooted. I am using the CP2112 as a USB-to-I2C adapter with two slave devices. Kernel version is 4.9.88. CP2112 silicon revision is F03. >From userspace, if I ctrl+c (^c) the output of the device file of one of the slaves, this occurs: [ 110.877415] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 111.909193] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 112.941004] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 113.973812] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 115.005627] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 116.037474] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 117.068261] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. [ 118.100093] cp2112 0003:10C4:EA90.0001: Transfer timed out, cancelling. The log message continues indefinitely; the clock is stuck high and the data line is stuck low. When we swap to a different I2C adapter in hardware, the bus lockup no longer occurs. Is there a modification I can make to the driver so that it can clear the bus, or recover the CP2112? I can forward some I2C traces if needed. Andrew
