>From newsserv!godzilla.zeta.org.au!bde Sat Aug 20 01:53:44 1994
From: newsserv!godzilla.zeta.org.au!bde (Bruce Evans)
Newsgroups: stark.freebsd-bugs
Subject: 1.1.5 fdprobe fails if cylinder > 67
Date: Thu, 4 Aug 94 00:27:25 +1000
Organization: Gene Stark's home system
Distribution: stark
NNTP-Posting-Host: home.stark.cs.sunysb.edu
To: freebsd-bugs@freefall.cdrom.com
Cc: joerg_wunsch@uriah.sax.de
Precedence: bulk

The floppy head is in an unknown position after booting.  If it's on a
cylinder > 67, then stepping it out 10 moves it to a cylinder > 77, so
recalibration will set NE7_ST0_EC and fdprobe() will fail.  If it's on
a cylinder less than 10 from the end, then stepping it out 10 may
damage it.

I think the BIOS usually leaves the head near cylinder 0 and then there
is no problem.  I think booting from a floppy leaves it on the last
cylinder accessed.  My boot disk contains 2 kernels and is almost full,
so at least one of them is likely to end near the last cylinder.

My fix adds 1 second to the probe for each drive.  The floppy probe
already has 2.3 seconds of delays per drive, so it now has 3.3 seconds
of annoying delays per drive :-).

The diff includes some cosmetic fixes.  spinwait() should not exist,
and isn't called except from recent versions of fd.c.

Bruce

*** sysc/i386/isa/fd.c	Sun May 22 22:30:14 1994
--- src/sys/i386/isa/fd.c	Wed Aug  3 23:26:04 1994
***************
*** 344,352 ****
  		/* select it */
  		set_motor(fdcu, fdsu, TURNON);
! 		spinwait(1000);	/* 1 sec */
  		out_fdc(fdcu, NE7CMD_SEEK);	/* seek some steps... */
  		out_fdc(fdcu, fdsu);
  		out_fdc(fdcu, 10);
! 		spinwait(300);			/* ...wait a moment... */
  		out_fdc(fdcu, NE7CMD_SENSEI);	/* make controller happy */
  		(void)in_fdc(fdcu);
--- 345,359 ----
  		/* select it */
  		set_motor(fdcu, fdsu, TURNON);
! 		DELAY(1000000);			/* 1 sec */
! 		out_fdc(fdcu, NE7CMD_RECAL);	/* avoid seeking off end */
! 		out_fdc(fdcu, fdsu);
! 		DELAY(1000000);	/* a second be enough for full stroke seek */
! 		out_fdc(fdcu, NE7CMD_SENSEI);	/* make controller happy */
! 		(void)in_fdc(fdcu);
! 		(void)in_fdc(fdcu);
  		out_fdc(fdcu, NE7CMD_SEEK);	/* seek some steps... */
  		out_fdc(fdcu, fdsu);
  		out_fdc(fdcu, 10);
! 		DELAY(300000);			/* ...wait a moment... */
  		out_fdc(fdcu, NE7CMD_SENSEI);	/* make controller happy */
  		(void)in_fdc(fdcu);
***************
*** 354,358 ****
  		out_fdc(fdcu, NE7CMD_RECAL);	/* ...and go back to 0 */
  		out_fdc(fdcu, fdsu);
! 		spinwait(1000);	/* a second be enough for full stroke seek */
  
  		/* anything responding */
--- 361,365 ----
  		out_fdc(fdcu, NE7CMD_RECAL);	/* ...and go back to 0 */
  		out_fdc(fdcu, fdsu);
! 		DELAY(1000000);	/* a second be enough for full stroke seek */
  
  		/* anything responding */
***************
*** 735,739 ****
  bad:
  	biodone(bp);
- 	return;
  }
  
--- 742,745 ----