I upgraded kernel to 2.6.34, and found that this kernel doesn't work correctly with my UPS USB->serial (cypress_m8 based). ttyUSB0 was successfully created, but nut can't read response from UPSю Фе startup I get such message: Network UPS Tools - UPS driver controller 2.4.1 Network UPS Tools - PowerCom protocol UPS driver 0.12 (2.4.1) data receiving error (0 instead of 16 bytes) data receiving error (0 instead of 16 bytes) After switching back to sys-kernel/gentoo-sources-2.6.32-r7 kernel - all working OK. Reproducible: Always Steps to Reproduce: Install Gentoo with sys-kernel/gentoo-sources-2.6.34 + sys-power/nut-2.4.1-r1, configure nut for Powercom UPS, connect UPS and try to start upsdrv.
Created attachment 235663 [details] current kernel config
kernel: potential breakage in USB stack?
USB flash works OK, also all is OK on my netbook (Gentoo/2.6.34) with Quallcom modem (uses modules `usbserial` and `option`). So it looks like trouble is in cypress_m8...
Yes, trouble is really in cypress_m8 driver - I've compiled driver from 2.6.32 kernel, and it works perfect.
We'll watch the upstream bug and port any resultant patches to earlier kernels.