CVS commit: src/sys/dev/usb

["Tom Ivar Helbekkmo" <tih%netbsd.org@localhost>]

Module Name:    src
Committed By:   tih
Date:           Sun Mar 29 10:46:10 UTC 2020

Modified Files:
        src/sys/dev/usb: ukbd.c

Log Message:
Summary: Introduce a keyboard event ring buffer for USB console keyboards

For the console keyboard, events must be handled separately from the
interrupt handler, because of the possibility that the user chooses to
drop into DDB by use of the designated key combination.  This delayed
handling is tied to the HZ clock through the callout(9) mechanism,
meaning that another keyboard event arriving within 10ms of the
previous one might overwrite its predecessor before it's handled.
This causes dropped events for fast typists - and the situation gets
worse with modern, programmable, keyboards.

This patch introduces a ring buffer in the ukbd_softc data structure,
so that multiple pending events may be safely stored.


To generate a diff of this commit:
cvs rdiff -u -r1.145 -r1.146 src/sys/dev/usb/ukbd.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.