Johan Hovold wrote: > On Sat, Jul 04, 2015 at 08:03:57PM +0300, Evgen Druzhynin wrote: > > [1.] One line summary of the problem: > > ch341 module fails on 4.1.1 kernel > > > > [2.] Full description of the problem/report: > > It's not possible to work with Arduino board after installing 4.1.1. > > ch341 fails and does not create /dev/ttyUSB0 (or /dev/ttyACM0) entry. > > On 3.18 and 4.0.0 all was ok. > > This does not look like a usb-serial issue (as no suspicious change went > into 4.1), but could possibly indicate a problem with the underlying > xhci driver (I've added the xhci-maintainer Mathias on CC). Unrelated, but I also have some ch341 hardware, and mine does not work with the mainline driver, it does however work reliably with the vendor driver. The two drivers initialize the hardware fairly differently, especially the baudrate generator, and the mainline driver doesn't support all control signals and modes. A few things are obvious and easy for me to fix and post, but I'm not sure how to proceed with the more complicated things; the baudrate seems to have two settings, one clock divisor set on init and another set depending on the selected baudrate. Mainline uses a different algorithm to set these than the vendor driver. I notice that my hardware version is more recent than the mainline driver was written for. I also notice that my hardware does not respond according to the expectations documented in mainline comments. Your thoughts? I know that another person was also working on this. //Peter -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
