kern/59917: ata reset update in ATAng

[Bruce Evans]

On Wed, 3 Dec 2003, Divacky Roman wrote:

> >Description:
>
> I have PIIX4 ata controller has very slow ata-reset under ATAng

How slow?  The patch seesm to mainly just increase the resolution of
the polling so that you have to wait up to 99 msec less.

> >How-To-Repeat:
>
> this is default behaviour
>
> >Fix:
> this patch fixes it:
>
> --- /tmp/ata-lowlevel.c	Sat Nov 22 16:48:27 2003
> +++ /sys/dev/ata/ata-lowlevel.c	Sat Nov 22 17:06:45 2003
> @@ -549,19 +549,22 @@
>      ATA_IDX_INB(ch, ATA_ERROR);
>
>      /* wait for BUSY to go inactive */
> -    for (timeout = 0; timeout < 310; timeout++) {
> +    /* Hacked by neologism... too slow for me ;) */
> +    for (timeout = 0; timeout < 31000; timeout++) {

I use similar changes (this and the corresponding decreased delay) for
unrelated reasons (to monitor the status in closer to real time).

>  	if (stat0 & ATA_S_BUSY) {
>  	    ATA_IDX_OUTB(ch, ATA_DRIVE, ATA_D_IBM | ATA_MASTER);
>  	    DELAY(10);
> -    	    err = ATA_IDX_INB(ch, ATA_ERROR);
> -	    lsb = ATA_IDX_INB(ch, ATA_CYL_LSB);
> -	    msb = ATA_IDX_INB(ch, ATA_CYL_MSB);
>  	    stat0 = ATA_IDX_INB(ch, ATA_STATUS);
> -	    if (bootverbose)
> -		ata_printf(ch, ATA_MASTER,
> -			   "stat=0x%02x err=0x%02x lsb=0x%02x msb=0x%02x\n",
> -			   stat0, err, lsb, msb);
>  	    if (!(stat0 & ATA_S_BUSY)) {
> +	       /* this should be there because of that condition...
> +		  dont know why sos did this... */
> +   	       err = ATA_IDX_INB(ch, ATA_ERROR);
> +   	       lsb = ATA_IDX_INB(ch, ATA_CYL_LSB);
> +   	       msb = ATA_IDX_INB(ch, ATA_CYL_MSB);
> +	       if (bootverbose)
> +  		  ata_printf(ch, ATA_MASTER,
> +			"stat=0x%02x err=0x%02x lsb=0x%02x msb=0x%02x\n",
> +			stat0, err, lsb, msb);
>  		if ((err & 0x7f) == ATA_E_ILI) {
>  		    if (lsb == ATAPI_MAGIC_LSB && msb == ATAPI_MAGIC_MSB) {
>  			ch->devices |= ATA_ATAPI_MASTER;

I use similar changes to avoid spec violations.  Unfortunately sos doesn't
like them.  The strange order is a hack which is claimed to help for some
out-of spec drives.  It only breaks in-spec drives sometimes (if a race is
lost).  On many systems the order makes no difference because we waited
a long time before beginning the loop, so all drives are already unbusy.

Bruce