On 11/12/18 10:54 AM, Johan Hovold wrote:
On Wed, Oct 31, 2018 at 09:16:48PM +0100, Nikolaj Fogh wrote:
I have experienced that the ftdi_sio driver gives less-than-optimal baud rates as the driver truncates instead of rounds to nearest during baud rate divisor calculation.
Please break your lines at 72 cols or so, and use the common subject
prefix (e.g. "USB: serial: ftdi_sio: improve...") with a concise
summary.
Ok. I will do that in the future.
This patch improves on the baud rate generation. The generated baud rate corresponds to the optimal baud rate achievable with the chip. This is what the windows driver gives as well.
How did you verify this? Did you trace and compare the divisors
actually requested by the Windows driver, or did you measure the
resulting rates using a scope?
Thanks,
Johan
I verified it by scope. Granted, I only verified it for one baud rate
(961200). Whether it gives the same as the Windows driver in general,
I'm not sure. However, I would think that rounding instead of flooring
would always yield the most accurate result.
Best regards
Nikolaj Fogh
