Date: Sun, 1 Jun 1997 22:10:01 -0700 (PDT) From: Donn Miller <dmm125@bellatlantic.net> To: freebsd-bugs Subject: Re: kern/3739: pause key not disabled; weird stuff when pressed Message-ID: <199706020510.WAA27121@hub.freebsd.org>
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The following reply was made to PR kern/3739; it has been noted by GNATS. From: Donn Miller <dmm125@bellatlantic.net> To: Kazutaka YOKOTA <yokota@zodiac.mech.utsunomiya-u.ac.jp> Cc: freebsd-gnats-submit@freebsd.org, yokota@freebsd.org Subject: Re: kern/3739: pause key not disabled; weird stuff when pressed Date: Mon, 2 Jun 1997 00:59:00 +0000 (GMT) On Mon, 2 Jun 1997, Donn Miller wrote: > > On Mon, 2 Jun 1997, Kazutaka YOKOTA wrote: > > > >>Number: 3739 > > >>Category: kern > > >>Synopsis: pause key not disabled; weird stuff when pressed > > >>Confidential: no > > >>Severity: non-critical > > >>Priority: medium > > >>Responsible: freebsd-bugs > > >>State: open > > >>Class: sw-bug > > >>Submitter-Id: current-users > > >>Arrival-Date: Sun Jun 1 07:40:01 PDT 1997 > > >>Last-Modified: > > >>Originator: Donn Miller > > >>Organization: > > >>Release: 2.2.2-RELEASE > > >>Environment: > > >FreeBSD myname.my.domain 2.2.2-RELEASE FreeBSD 2.2.2-RELEASE #2: Sun Jun 1 06 > > >:5 > > >3:20 GMT 1997 root@myname.my.domain:/usr/src/sys/compile/CUSTOM i386 > > >>Description: > > >The pause key is not disabled on the AT keyboard. When 'pause' is hit > > >(like during 'cat' of a large file) some weird stuff happens. > > > > The console driver `syscons' has the `back-scroll' feature which is > > activated by the `Scroll-Lock' or `Pause' keys. When one of these keys > > is pressed, the screen output is suspended and you can `back scroll' > > lines recently printed on the screen. You navigate through the lines > > with `Page-up/down', `Home', `End' and `Up/Down' keys. > > > > The `Scroll Lock' LED should be on while in this mode. > > > > >The file will resume scrolling only after pressing 'pause' key > > >2 or 3 times. > > > > Just one press should bring you back to the normal output mode... > > > > >After the scrolling of text is finished, the key > > >mappings are screwed-up. For example, pressing p is the same as > > >'left arrow', the s key does something else, etc. If you press ^C, the shell > > >exits. If you press scroll lock about 5 times, followed by ^C, the terminal i > > >s restored. > > > > We may be seeing strange interaction between the output routine, the > > `back scroll' routine and keyboard I/O routines. I think I know what happens here: on (U.S.) PC's, the 'pause' key is tied to a particular BIOS routine that pauses whatever output is being sent to the screen. However, the syscons driver wants to do another routine when this key is pressed. Maybe the interaction between the BIOS activities and the syscons driver is causing weird things to happen. This is similar to the BIOS routine that reboots the machine when cntrl-alt-delete is pressed. A possible solution would be to 'trap' the pause key to prevent the BIOS from intervening, if this is what's happening. Then, the syscons driver would be free to assign the sroll-back routine to the pause key. I think this because I think under plain DOS, many BIOS activities are left alone to their default values, and the pause key does a particular thing there. Hopefully, I have been a little more clear on this. Thanks, Donn (dmm125@bellatlantic.net)
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