On Tue, Jul 07, 2020 at 04:53:22PM +0200, Michael Hanselmann wrote: > On devices which do not support break signalling a break condition is > simulated by sending a NUL byte at the lowest possible speed. The break > condition will be 9 bit periods long (start bit and eight data bits), > but the transmission itself also includes the stop bit. The safety > margin of one bit is kept to account for timing differences. > > Signed-off-by: Michael Hanselmann <public@xxxxxxxxx> > --- > > Hi Johan > > On 07.07.20 08:19, Johan Hovold wrote: > > I reread the break-end comment and found it a bit confusing still. The > > below seems more correct to me. I'm assuming you did not intend to add > > an additional bit period as margin? > > The additional bit was intentional, but I missed the start bit and was > off by one. As such your fix indeed addresses the inconsistency between > the comment and code. Considering the general quality of the ch341 > chips needing the simulation and to account for timing differences I'd > instead prefer to increase the delay from 10 to 11 bits (1 start, 8 data, > 1 stop, 1 margin). Thanks for confirming. I've applied this patch with a slightly modified commit message: https://git.kernel.org/pub/scm/linux/kernel/git/johan/usb-serial.git/commit/?h=usb-next Johan
