[PARPORT] BUG FIXES re: HP CD-R and pg !!

Tue, 16 Jun 1998 08:13:29 -0400 (EDT)

After a week of silence, I've got a flood of very useful messages concerning
pg and cdrecord. I believe that most of the problems have now been identified
and fixed.

> pg0: HP CD-Writer+ 7200, slave
> to load it I had to change PG_TMO to 100.

Actually, PG_TMO should be == HZ (which is == 100) but the timeout in
pg_reset should be more like 10*HZ. I will define a new constant for

Other minor problems:

- PI_PG is not defined in the pg-beta patch kit, but is if you use
   2.1.106. PI_PG should be defined to 4 in paride.h

- There's an Ugh when you load pg - and probably the other paride
   high level drivers - on some systems. The temporary patch for this
   is to comment out the two "cli()" calls in the module initialisation
   code - they are paranoid programming only. I will find the correct
   patch ASAP.

- The macro MAX may not be defined in your header files when you go
   to build scsi-linux-pg.c - Joerg's makefiles rather hide the cause,
   too. If necessary, put

        #define MAX(a,b) ((a)>(b)?(a):(b))

   just before MAX is used in scsi-linux-pg.c.

And there is one more serious bug that shows up when you do a write on
the HP 7xxx drives.

> Blocks total: 333750 Blocks remaining: 333750
> resid: 48
> cdrecord: Timer expired. Cannot send SCSI cmd via ioctl

To fix this you need to make some changes in pg.c in the pg_completion
function. It should read:

static int pg_completion( int unit, char * buf, int tmo)

{ int r, d, n, p;

        r = pg_wait(unit,STAT_BUSY,STAT_DRQ|STAT_READY|STAT_ERR,

        PG.dlen = 0;

        while (RR(0,7)&STAT_DRQ) {
           d = (RR(0,4)+256*RR(0,5));
           n = ((d+3)&0xfffc);
           p = RR(0,2)&3;
           if (p == 0) pi_write_block(PI,buf,n);
           if (p == 2) pi_read_block(PI,buf,n);
           if (verbose > 1) printk("%s: %s %d bytes\n",PG.name,
           PG.dlen += (1-p)*d;
           buf += d;
           r = pg_wait(unit,STAT_BUSY,STAT_DRQ|STAT_READY|STAT_ERR,


        return r;

Basically, this puts a loop back that used to be in a different
function that got eliminated :-(

I'm going to submit the kernel patches to repair these things and
do a new pg_beta.tar as soon as I can, but that might not be today.

Grant R. Guenther grant@torque.net

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