On a fresh install of Yosemite my USB CDC ACM device fails badly.
This is an open firmware/hardware CNC-controller called TOAD4 that I use in my EazyCNC software, more info here: http://www.eazycnc.com The controller presents itself as a USB CDC ACM to the OS. The firmware has been stable for years and the communication works without issues in several operating system, it has been tested in numerous Linuxes, Windows XP, Windows 7 and Mac OS X Lion, Mountain Lion (possibly/probably on Maverik too). I use it daily on Mountain Lion without issues. Now, on Yosemite it seems that within tens of seconds of opening the virtual serial port a read timeouts and the device disappears from the /dev directory. And it won't reappear there even after re-pluggin the device although the device is still running according to the external signs I can observer on the device. I need to physically reset the device to make it re-appear in the /dev directory. Now the fact that it won't re-appear after re-plugging, suggest something is wrong on the device side firmware. With every other (than Yosemite) operating system I've tested the system the OS has no problem enumerating the device after a re-plug. However the primary problem is that something goes south during normal communication and this I'm not convinced is a device side issue. Of course it can be a device side firmware issue, not denying that. The USB CDC ACM 'stack' on the device is a bare minimum supporting only the absolutely mandatory features as per the USB spec. Googling around I see that several virtual devices both custom driver based (FTDI) and Apple driver based (ie real USB CDC ACM devices) have experienced problems with Yosemite. Now I'm looking for ideas on how to debug this further and also fishing for info on what has changed on Yosemite and hunches about what could be the problem. br Kusti -- Sent with Postbox <http://www.getpostbox.com>
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