Module Name:	syssrc
Committed By:	wdk
Date:		Mon Jun 25 08:30:12 UTC 2001

Modified Files:
	syssrc/sys/dev/ic: z8530sc.c

Log Message:
Don't reprogram SCC registers unless the values have changed.

Some CMOS Z85C30 SCC's (as used in the SGI Indy and Mips Magnum 3000's)
reset the baud rate generator when a new prescaler is loaded - despite
what is documented in the datasheet.

Avoids "character glitch" problems when line discipline characteristics
are changed at the start of the login process, or during a ftp session
on the /dev/console device.

Tested on -sgimips, -mipsco and -alpha platforms


To generate a diff of this commit:
cvs rdiff -r1.12 -r1.13 syssrc/sys/dev/ic/z8530sc.c

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