kern/84799: can't read beyond track 0 on fdc (IBM thinkpad G40)

[Joost Bekkers]

The following reply was made to PR kern/84799; it has been noted by GNATS.

From: Joost Bekkers <joost at jodocus.org>
To: bug-followup at FreeBSD.org
Cc:  
Subject: Re: kern/84799: can't read beyond track 0 on fdc (IBM thinkpad G40)
Date: Fri, 12 Aug 2005 19:40:55 +0200

 This seems to me a nice way to work around the faulty hardware.
 (diff against 6.0-B2, but should work on 5 too)
 
 diff -u fdc.dist/fdc.c fdc/fdc.c
 --- fdc.dist/fdc.c	Fri Aug 12 19:24:39 2005
 +++ fdc/fdc.c	Fri Aug 12 19:27:15 2005
 @@ -736,7 +736,7 @@
  	struct bio *bp;
  	int i, nsect;
  	int st0, st3, cyl, mfm, steptrac, cylinder, descyl, sec;
 -	int head;
 +	int head,prev_track;
  	static int need_recal;
  	struct fdc_readid *idp;
  	struct fd_formb *finfo;
 @@ -953,7 +953,8 @@
  	if (cylinder != fd->track && (
  	    fdc->fdct != FDC_ENHANCED ||
  	    descyl != cylinder ||
 -	    (bp->bio_cmd & (BIO_RDID|BIO_FMT)))) {
 +	    (bp->bio_cmd & (BIO_RDID|BIO_FMT)) ||
 +	    (fdc->flags & FDC_NEEDSEEK))) {
  		retry_line = __LINE__;
  		if (fdc_cmd(fdc, 3, NE7CMD_SEEK, fd->fdsu, descyl, 0))
  			return (1);
 @@ -970,6 +971,7 @@
  		if (settle)
  			msleep(fdc->fd, NULL, PRIBIO, "fdhdstl", settle);
  	}
 +	prev_track=fd->track;
  	fd->track = cylinder;
  
  	if (debugflags & 8)
 @@ -1114,6 +1116,11 @@
  		}
  		retry_line = __LINE__;
  		if(st0 == NE7_ST0_IC_AT && fdc->status[2] & NE7_ST2_WC) {
 +			if (prev_track==0 && 
 +			    cylinder!=0 &&
 +                            !(fdc->flags & FDC_NEEDSEEK)) {
 +				fdc->flags|=FDC_NEEDSEEK;
 +			}
  			need_recal |= (1 << fd->fdsu);
  			return (1);
  		}
 diff -u fdc.dist/fdcvar.h fdc/fdcvar.h
 --- fdc.dist/fdcvar.h	Fri Aug 12 19:25:05 2005
 +++ fdc/fdcvar.h	Thu Aug 11 18:27:43 2005
 @@ -40,6 +40,7 @@
  	int	dmachan;
  	int	flags;
  #define FDC_HASDMA	0x01
 +#define FDC_NEEDSEEK	0x02	/* enhanced controller that needs expl seek */
  #define FDC_STAT_VALID	0x08
  #define FDC_HAS_FIFO	0x10
  #define FDC_NEEDS_RESET	0x20