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st_scsi.c revision 1.2.4.2
      1  1.2.4.2  thorpej /*	$NetBSD: st_scsi.c,v 1.2.4.2 2002/01/10 19:58:30 thorpej Exp $ */
      2      1.1   bouyer 
      3      1.1   bouyer /*-
      4      1.1   bouyer  * Copyright (c) 1998 The NetBSD Foundation, Inc.
      5      1.1   bouyer  * All rights reserved.
      6      1.1   bouyer  *
      7      1.1   bouyer  * This code is derived from software contributed to The NetBSD Foundation
      8      1.1   bouyer  * by Charles M. Hannum.
      9      1.1   bouyer  *
     10      1.1   bouyer  * Redistribution and use in source and binary forms, with or without
     11      1.1   bouyer  * modification, are permitted provided that the following conditions
     12      1.1   bouyer  * are met:
     13      1.1   bouyer  * 1. Redistributions of source code must retain the above copyright
     14      1.1   bouyer  *    notice, this list of conditions and the following disclaimer.
     15      1.1   bouyer  * 2. Redistributions in binary form must reproduce the above copyright
     16      1.1   bouyer  *    notice, this list of conditions and the following disclaimer in the
     17      1.1   bouyer  *    documentation and/or other materials provided with the distribution.
     18      1.1   bouyer  * 3. All advertising materials mentioning features or use of this software
     19      1.1   bouyer  *    must display the following acknowledgement:
     20      1.1   bouyer  *        This product includes software developed by the NetBSD
     21      1.1   bouyer  *        Foundation, Inc. and its contributors.
     22      1.1   bouyer  * 4. Neither the name of The NetBSD Foundation nor the names of its
     23      1.1   bouyer  *    contributors may be used to endorse or promote products derived
     24      1.1   bouyer  *    from this software without specific prior written permission.
     25      1.1   bouyer  *
     26      1.1   bouyer  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     27      1.1   bouyer  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     28      1.1   bouyer  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     29      1.1   bouyer  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     30      1.1   bouyer  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     31      1.1   bouyer  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     32      1.1   bouyer  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     33      1.1   bouyer  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     34      1.1   bouyer  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     35      1.1   bouyer  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     36      1.1   bouyer  * POSSIBILITY OF SUCH DAMAGE.
     37      1.1   bouyer  */
     38      1.1   bouyer 
     39      1.1   bouyer /*
     40      1.1   bouyer  * Originally written by Julian Elischer (julian (at) tfs.com)
     41      1.1   bouyer  * for TRW Financial Systems for use under the MACH(2.5) operating system.
     42      1.1   bouyer  *
     43      1.1   bouyer  * TRW Financial Systems, in accordance with their agreement with Carnegie
     44      1.1   bouyer  * Mellon University, makes this software available to CMU to distribute
     45      1.1   bouyer  * or use in any manner that they see fit as long as this message is kept with
     46      1.1   bouyer  * the software. For this reason TFS also grants any other persons or
     47      1.1   bouyer  * organisations permission to use or modify this software.
     48      1.1   bouyer  *
     49      1.1   bouyer  * TFS supplies this software to be publicly redistributed
     50      1.1   bouyer  * on the understanding that TFS is not responsible for the correct
     51      1.1   bouyer  * functioning of this software in any circumstances.
     52      1.1   bouyer  *
     53      1.1   bouyer  * Ported to run under 386BSD by Julian Elischer (julian (at) tfs.com) Sept 1992
     54      1.1   bouyer  * major changes by Julian Elischer (julian (at) jules.dialix.oz.au) May 1993
     55      1.1   bouyer  *
     56      1.1   bouyer  * A lot of rewhacking done by mjacob (mjacob (at) nas.nasa.gov).
     57      1.1   bouyer  */
     58      1.1   bouyer 
     59  1.2.4.2  thorpej #include <sys/cdefs.h>
     60  1.2.4.2  thorpej __KERNEL_RCSID(0, "$NetBSD: st_scsi.c,v 1.2.4.2 2002/01/10 19:58:30 thorpej Exp $");
     61  1.2.4.2  thorpej 
     62      1.1   bouyer #include "opt_scsi.h"
     63      1.1   bouyer #include "rnd.h"
     64      1.1   bouyer 
     65      1.1   bouyer #include <sys/param.h>
     66      1.1   bouyer #include <sys/device.h>
     67      1.1   bouyer #include <sys/buf.h>
     68      1.1   bouyer #include <sys/conf.h>
     69      1.1   bouyer #include <sys/kernel.h>
     70      1.2   bouyer #include <sys/systm.h>
     71      1.1   bouyer 
     72      1.1   bouyer #include <dev/scsipi/stvar.h>
     73      1.2   bouyer #include <dev/scsipi/scsi_tape.h>
     74      1.2   bouyer #include <dev/scsipi/scsi_all.h>
     75      1.1   bouyer 
     76      1.1   bouyer int	st_scsibus_match __P((struct device *, struct cfdata *, void *));
     77      1.2   bouyer void	st_scsibus_attach __P((struct device *, struct device *, void *));
     78      1.2   bouyer int	st_scsibus_ops __P((struct st_softc *, int, int));
     79      1.2   bouyer int	st_scsibus_read_block_limits __P((struct st_softc *, int));
     80      1.2   bouyer int	st_scsibus_mode_sense __P((struct st_softc *, int));
     81      1.2   bouyer int	st_scsibus_mode_select __P((struct st_softc *, int));
     82      1.2   bouyer int	st_scsibus_cmprss __P((struct st_softc *, int, int));
     83      1.1   bouyer 
     84      1.1   bouyer struct cfattach st_scsibus_ca = {
     85  1.2.4.2  thorpej 	sizeof(struct st_softc), st_scsibus_match, st_scsibus_attach,
     86  1.2.4.2  thorpej 	stdetach, stactivate
     87      1.1   bouyer };
     88      1.1   bouyer 
     89      1.1   bouyer const struct scsipi_inquiry_pattern st_scsibus_patterns[] = {
     90      1.1   bouyer 	{T_SEQUENTIAL, T_REMOV,
     91      1.1   bouyer 	 "",         "",                 ""},
     92      1.1   bouyer };
     93      1.1   bouyer 
     94      1.1   bouyer int
     95      1.1   bouyer st_scsibus_match(parent, match, aux)
     96      1.1   bouyer 	struct device *parent;
     97      1.1   bouyer 	struct cfdata *match;
     98      1.1   bouyer 	void *aux;
     99      1.1   bouyer {
    100      1.1   bouyer 	struct scsipibus_attach_args *sa = aux;
    101      1.1   bouyer 	int priority;
    102      1.1   bouyer 
    103      1.2   bouyer 	if (scsipi_periph_bustype(sa->sa_periph) != SCSIPI_BUSTYPE_SCSI)
    104      1.2   bouyer 		return (0);
    105      1.2   bouyer 
    106      1.1   bouyer 	(void)scsipi_inqmatch(&sa->sa_inqbuf,
    107      1.1   bouyer 	    (caddr_t)st_scsibus_patterns,
    108      1.1   bouyer 	    sizeof(st_scsibus_patterns)/sizeof(st_scsibus_patterns[0]),
    109      1.1   bouyer 	    sizeof(st_scsibus_patterns[0]), &priority);
    110      1.1   bouyer 	return (priority);
    111      1.2   bouyer }
    112      1.2   bouyer 
    113      1.2   bouyer void
    114      1.2   bouyer st_scsibus_attach(parent, self, aux)
    115      1.2   bouyer 	struct device *parent, *self;
    116      1.2   bouyer 	void *aux;
    117      1.2   bouyer {
    118      1.2   bouyer 	struct st_softc *st = (void *)self;
    119      1.2   bouyer 
    120      1.2   bouyer 	st->ops = st_scsibus_ops;
    121      1.2   bouyer 	stattach(parent, st, aux);
    122      1.2   bouyer }
    123      1.2   bouyer 
    124      1.2   bouyer int
    125      1.2   bouyer st_scsibus_ops(st, op, flags)
    126      1.2   bouyer 	struct st_softc *st;
    127      1.2   bouyer 	int op;
    128      1.2   bouyer 	int flags;
    129      1.2   bouyer {
    130      1.2   bouyer 	switch(op) {
    131      1.2   bouyer 	case ST_OPS_RBL:
    132      1.2   bouyer 		return st_scsibus_read_block_limits(st, flags);
    133      1.2   bouyer 	case ST_OPS_MODESENSE:
    134      1.2   bouyer 		return st_scsibus_mode_sense(st, flags);
    135      1.2   bouyer 	case ST_OPS_MODESELECT:
    136      1.2   bouyer 		return st_scsibus_mode_select(st, flags);
    137      1.2   bouyer 	case ST_OPS_CMPRSS_ON:
    138      1.2   bouyer 	case ST_OPS_CMPRSS_OFF:
    139      1.2   bouyer 		return st_scsibus_cmprss(st, flags,
    140      1.2   bouyer 		    (op == ST_OPS_CMPRSS_ON) ? 1 : 0);
    141      1.2   bouyer 	default:
    142      1.2   bouyer 		panic("st_scsibus_ops: invalid op");
    143      1.2   bouyer 		return 0; /* XXX to appease gcc */
    144      1.2   bouyer 	}
    145      1.2   bouyer 	/* NOTREACHED */
    146      1.2   bouyer }
    147      1.2   bouyer 
    148      1.2   bouyer /*
    149      1.2   bouyer  * Ask the drive what it's min and max blk sizes are.
    150      1.2   bouyer  */
    151      1.2   bouyer int
    152      1.2   bouyer st_scsibus_read_block_limits(st, flags)
    153      1.2   bouyer 	struct st_softc *st;
    154      1.2   bouyer 	int flags;
    155      1.2   bouyer {
    156      1.2   bouyer 	struct scsi_block_limits cmd;
    157      1.2   bouyer 	struct scsi_block_limits_data block_limits;
    158      1.2   bouyer 	struct scsipi_periph *periph = st->sc_periph;
    159      1.2   bouyer 	int error;
    160      1.2   bouyer 
    161      1.2   bouyer 	/*
    162      1.2   bouyer 	 * do a 'Read Block Limits'
    163      1.2   bouyer 	 */
    164  1.2.4.1    lukem 	memset(&cmd, 0, sizeof(cmd));
    165      1.2   bouyer 	cmd.opcode = READ_BLOCK_LIMITS;
    166      1.2   bouyer 
    167      1.2   bouyer 	/*
    168      1.2   bouyer 	 * do the command, update the global values
    169      1.2   bouyer 	 */
    170      1.2   bouyer 	error = scsipi_command(periph, (struct scsipi_generic *)&cmd,
    171      1.2   bouyer 	    sizeof(cmd), (u_char *)&block_limits, sizeof(block_limits),
    172      1.2   bouyer 	    ST_RETRIES, ST_CTL_TIME, NULL,
    173      1.2   bouyer 	    flags | XS_CTL_DATA_IN | XS_CTL_DATA_ONSTACK);
    174      1.2   bouyer 	if (error)
    175      1.2   bouyer 		return (error);
    176      1.2   bouyer 
    177      1.2   bouyer 	st->blkmin = _2btol(block_limits.min_length);
    178      1.2   bouyer 	st->blkmax = _3btol(block_limits.max_length);
    179      1.2   bouyer 
    180      1.2   bouyer 	SC_DEBUG(periph, SCSIPI_DB3,
    181      1.2   bouyer 	    ("(%d <= blksize <= %d)\n", st->blkmin, st->blkmax));
    182      1.2   bouyer 	return (0);
    183      1.2   bouyer }
    184      1.2   bouyer 
    185      1.2   bouyer /*
    186      1.2   bouyer  * Get the scsi driver to send a full inquiry to the
    187      1.2   bouyer  * device and use the results to fill out the global
    188      1.2   bouyer  * parameter structure.
    189      1.2   bouyer  *
    190      1.2   bouyer  * called from:
    191      1.2   bouyer  * attach
    192      1.2   bouyer  * open
    193      1.2   bouyer  * ioctl (to reset original blksize)
    194      1.2   bouyer  */
    195      1.2   bouyer int
    196      1.2   bouyer st_scsibus_mode_sense(st, flags)
    197      1.2   bouyer 	struct st_softc *st;
    198      1.2   bouyer 	int flags;
    199      1.2   bouyer {
    200      1.2   bouyer 	u_int scsipi_sense_len;
    201      1.2   bouyer 	int error;
    202      1.2   bouyer 	struct scsipi_sense {
    203      1.2   bouyer 		struct scsipi_mode_header header;
    204      1.2   bouyer 		struct scsi_blk_desc blk_desc;
    205      1.2   bouyer 		u_char sense_data[MAX_PAGE_0_SIZE];
    206      1.2   bouyer 	} scsipi_sense;
    207      1.2   bouyer 	struct scsipi_periph *periph = st->sc_periph;
    208      1.2   bouyer 
    209      1.2   bouyer 	scsipi_sense_len = 12 + st->page_0_size;
    210      1.2   bouyer 
    211      1.2   bouyer 	/*
    212      1.2   bouyer 	 * Set up a mode sense
    213      1.2   bouyer 	 * We don't need the results. Just print them for our interest's sake,
    214      1.2   bouyer 	 * if asked, or if we need it as a template for the mode select store
    215      1.2   bouyer 	 * it away.
    216      1.2   bouyer 	 */
    217      1.2   bouyer 	error = scsipi_mode_sense(st->sc_periph, 0, SMS_PAGE_CTRL_CURRENT,
    218      1.2   bouyer 	    &scsipi_sense.header, scsipi_sense_len, flags | XS_CTL_DATA_ONSTACK,
    219      1.2   bouyer 	    ST_RETRIES, ST_CTL_TIME);
    220      1.2   bouyer 	if (error)
    221      1.2   bouyer 		return (error);
    222      1.2   bouyer 
    223      1.2   bouyer 	st->numblks = _3btol(scsipi_sense.blk_desc.nblocks);
    224      1.2   bouyer 	st->media_blksize = _3btol(scsipi_sense.blk_desc.blklen);
    225      1.2   bouyer 	st->media_density = scsipi_sense.blk_desc.density;
    226      1.2   bouyer 	if (scsipi_sense.header.dev_spec & SMH_DSP_WRITE_PROT)
    227      1.2   bouyer 		st->flags |= ST_READONLY;
    228      1.2   bouyer 	else
    229      1.2   bouyer 		st->flags &= ~ST_READONLY;
    230      1.2   bouyer 	SC_DEBUG(periph, SCSIPI_DB3,
    231      1.2   bouyer 	    ("density code %d, %d-byte blocks, write-%s, ",
    232      1.2   bouyer 	    st->media_density, st->media_blksize,
    233      1.2   bouyer 	    st->flags & ST_READONLY ? "protected" : "enabled"));
    234      1.2   bouyer 	SC_DEBUG(periph, SCSIPI_DB3,
    235      1.2   bouyer 	    ("%sbuffered\n",
    236      1.2   bouyer 	    scsipi_sense.header.dev_spec & SMH_DSP_BUFF_MODE ? "" : "un"));
    237      1.2   bouyer 	if (st->page_0_size)
    238  1.2.4.1    lukem 		memcpy(st->sense_data, scsipi_sense.sense_data,
    239      1.2   bouyer 		    st->page_0_size);
    240      1.2   bouyer 	periph->periph_flags |= PERIPH_MEDIA_LOADED;
    241      1.2   bouyer 	return (0);
    242      1.2   bouyer }
    243      1.2   bouyer 
    244      1.2   bouyer /*
    245      1.2   bouyer  * Send a filled out parameter structure to the drive to
    246      1.2   bouyer  * set it into the desire modes etc.
    247      1.2   bouyer  */
    248      1.2   bouyer int
    249      1.2   bouyer st_scsibus_mode_select(st, flags)
    250      1.2   bouyer 	struct st_softc *st;
    251      1.2   bouyer 	int flags;
    252      1.2   bouyer {
    253      1.2   bouyer 	u_int scsi_select_len;
    254      1.2   bouyer 	struct scsi_select {
    255      1.2   bouyer 		struct scsipi_mode_header header;
    256      1.2   bouyer 		struct scsi_blk_desc blk_desc;
    257      1.2   bouyer 		u_char sense_data[MAX_PAGE_0_SIZE];
    258      1.2   bouyer 	} scsi_select;
    259      1.2   bouyer 	struct scsipi_periph *periph = st->sc_periph;
    260      1.2   bouyer 
    261      1.2   bouyer 	scsi_select_len = 12 + st->page_0_size;
    262      1.2   bouyer 
    263      1.2   bouyer 	/*
    264      1.2   bouyer 	 * This quirk deals with drives that have only one valid mode
    265      1.2   bouyer 	 * and think this gives them license to reject all mode selects,
    266      1.2   bouyer 	 * even if the selected mode is the one that is supported.
    267      1.2   bouyer 	 */
    268      1.2   bouyer 	if (st->quirks & ST_Q_UNIMODAL) {
    269      1.2   bouyer 		SC_DEBUG(periph, SCSIPI_DB3,
    270      1.2   bouyer 		    ("not setting density 0x%x blksize 0x%x\n",
    271      1.2   bouyer 		    st->density, st->blksize));
    272      1.2   bouyer 		return (0);
    273      1.2   bouyer 	}
    274      1.2   bouyer 
    275      1.2   bouyer 	/*
    276      1.2   bouyer 	 * Set up for a mode select
    277      1.2   bouyer 	 */
    278  1.2.4.1    lukem 	memset(&scsi_select, 0, scsi_select_len);
    279      1.2   bouyer 	scsi_select.header.blk_desc_len = sizeof(struct scsi_blk_desc);
    280      1.2   bouyer 	scsi_select.header.dev_spec &= ~SMH_DSP_BUFF_MODE;
    281      1.2   bouyer 	scsi_select.blk_desc.density = st->density;
    282      1.2   bouyer 	if (st->flags & ST_DONTBUFFER)
    283      1.2   bouyer 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_OFF;
    284      1.2   bouyer 	else
    285      1.2   bouyer 		scsi_select.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
    286      1.2   bouyer 	if (st->flags & ST_FIXEDBLOCKS)
    287      1.2   bouyer 		_lto3b(st->blksize, scsi_select.blk_desc.blklen);
    288      1.2   bouyer 	if (st->page_0_size)
    289  1.2.4.1    lukem 		memcpy(scsi_select.sense_data, st->sense_data, st->page_0_size);
    290      1.2   bouyer 
    291      1.2   bouyer 	/*
    292      1.2   bouyer 	 * do the command
    293      1.2   bouyer 	 */
    294      1.2   bouyer 	return scsipi_mode_select(periph, 0, &scsi_select.header,
    295      1.2   bouyer 	    scsi_select_len, flags | XS_CTL_DATA_ONSTACK,
    296      1.2   bouyer 	    ST_RETRIES, ST_CTL_TIME);
    297      1.2   bouyer }
    298      1.2   bouyer 
    299      1.2   bouyer int
    300      1.2   bouyer st_scsibus_cmprss(st, flags, onoff)
    301      1.2   bouyer 	struct st_softc *st;
    302      1.2   bouyer 	int flags;
    303      1.2   bouyer 	int onoff;
    304      1.2   bouyer {
    305      1.2   bouyer 	u_int scsi_dlen;
    306      1.2   bouyer 	int byte2, page;
    307      1.2   bouyer 	struct scsi_select {
    308      1.2   bouyer 		struct scsipi_mode_header header;
    309      1.2   bouyer 		struct scsi_blk_desc blk_desc;
    310      1.2   bouyer 		u_char pdata[MAX(sizeof(struct scsi_tape_dev_conf_page),
    311      1.2   bouyer 		    sizeof(struct scsi_tape_dev_compression_page))];
    312      1.2   bouyer 	} scsi_pdata;
    313      1.2   bouyer 	struct scsi_tape_dev_conf_page *ptr;
    314      1.2   bouyer 	struct scsi_tape_dev_compression_page *cptr;
    315      1.2   bouyer 	struct scsipi_periph *periph = st->sc_periph;
    316      1.2   bouyer 	int error, ison;
    317      1.2   bouyer 
    318      1.2   bouyer 	scsi_dlen = sizeof(scsi_pdata);
    319      1.2   bouyer 	/*
    320      1.2   bouyer 	 * Do DATA COMPRESSION page first.
    321      1.2   bouyer 	 */
    322      1.2   bouyer 	page = SMS_PAGE_CTRL_CURRENT | 0xf;
    323      1.2   bouyer 	byte2 = 0;
    324      1.2   bouyer 
    325      1.2   bouyer 	/*
    326      1.2   bouyer 	 * Do the MODE SENSE command...
    327      1.2   bouyer 	 */
    328      1.2   bouyer again:
    329  1.2.4.1    lukem 	memset(&scsi_pdata, 0, scsi_dlen);
    330      1.2   bouyer 	error = scsipi_mode_sense(periph, byte2, page,
    331      1.2   bouyer 	    &scsi_pdata.header, scsi_dlen, flags | XS_CTL_DATA_ONSTACK,
    332      1.2   bouyer 	    ST_RETRIES, ST_CTL_TIME);
    333      1.2   bouyer 
    334      1.2   bouyer 	if (error) {
    335      1.2   bouyer 		if (byte2 != SMS_DBD) {
    336      1.2   bouyer 			byte2 = SMS_DBD;
    337      1.2   bouyer 			goto again;
    338      1.2   bouyer 		}
    339      1.2   bouyer 		/*
    340      1.2   bouyer 		 * Try a different page?
    341      1.2   bouyer 		 */
    342      1.2   bouyer 		if (page == (SMS_PAGE_CTRL_CURRENT | 0xf)) {
    343      1.2   bouyer 			page = SMS_PAGE_CTRL_CURRENT | 0x10;
    344      1.2   bouyer 			byte2 = 0;
    345      1.2   bouyer 			goto again;
    346      1.2   bouyer 		}
    347      1.2   bouyer 		return (error);
    348      1.2   bouyer 	}
    349      1.2   bouyer 
    350      1.2   bouyer 	if (scsi_pdata.header.blk_desc_len)
    351      1.2   bouyer 		ptr = (struct scsi_tape_dev_conf_page *) scsi_pdata.pdata;
    352      1.2   bouyer 	else
    353      1.2   bouyer 		ptr = (struct scsi_tape_dev_conf_page *) &scsi_pdata.blk_desc;
    354      1.2   bouyer 
    355      1.2   bouyer 	if ((page & SMS_PAGE_CODE) == 0xf) {
    356      1.2   bouyer 		cptr = (struct scsi_tape_dev_compression_page *) ptr;
    357      1.2   bouyer 		ison = (cptr->dce_dcc & DCP_DCE) != 0;
    358      1.2   bouyer 		if (onoff)
    359      1.2   bouyer 			cptr->dce_dcc |= DCP_DCE;
    360      1.2   bouyer 		else
    361      1.2   bouyer 			cptr->dce_dcc &= ~DCP_DCE;
    362      1.2   bouyer 		cptr->pagecode &= ~0x80;
    363      1.2   bouyer 	} else {
    364      1.2   bouyer 		ison =  (ptr->sel_comp_alg != 0);
    365      1.2   bouyer 		if (onoff)
    366      1.2   bouyer 			ptr->sel_comp_alg = 1;
    367      1.2   bouyer 		else
    368      1.2   bouyer 			ptr->sel_comp_alg = 0;
    369      1.2   bouyer 		ptr->pagecode &= ~0x80;
    370      1.2   bouyer 		ptr->byte2 = 0;
    371      1.2   bouyer 		ptr->active_partition = 0;
    372      1.2   bouyer 		ptr->wb_full_ratio = 0;
    373      1.2   bouyer 		ptr->rb_empty_ratio = 0;
    374      1.2   bouyer 		ptr->byte8 &= ~0x30;
    375      1.2   bouyer 		ptr->gap_size = 0;
    376      1.2   bouyer 		ptr->byte10 &= ~0xe7;
    377      1.2   bouyer 		ptr->ew_bufsize[0] = 0;
    378      1.2   bouyer 		ptr->ew_bufsize[1] = 0;
    379      1.2   bouyer 		ptr->ew_bufsize[2] = 0;
    380      1.2   bouyer 		ptr->reserved = 0;
    381      1.2   bouyer 	}
    382      1.2   bouyer 	/*
    383      1.2   bouyer 	 * There might be a virtue in actually doing the MODE SELECTS,
    384      1.2   bouyer 	 * but let's not clog the bus over it.
    385      1.2   bouyer 	 */
    386      1.2   bouyer 	if (onoff == ison)
    387      1.2   bouyer 		return (0);
    388      1.2   bouyer 
    389      1.2   bouyer 	/*
    390      1.2   bouyer 	 * Set up for a mode select
    391      1.2   bouyer 	 */
    392      1.2   bouyer 
    393      1.2   bouyer 	scsi_pdata.header.data_length = 0;
    394      1.2   bouyer 	scsi_pdata.header.medium_type = 0;
    395      1.2   bouyer 	if ((st->flags & ST_DONTBUFFER) == 0)
    396      1.2   bouyer 		scsi_pdata.header.dev_spec = SMH_DSP_BUFF_MODE_ON;
    397      1.2   bouyer 	else
    398      1.2   bouyer 		scsi_pdata.header.dev_spec = 0;
    399      1.2   bouyer 
    400      1.2   bouyer 	if (scsi_pdata.header.blk_desc_len) {
    401      1.2   bouyer 		scsi_pdata.blk_desc.density = 0;
    402      1.2   bouyer 		scsi_pdata.blk_desc.nblocks[0] = 0;
    403      1.2   bouyer 		scsi_pdata.blk_desc.nblocks[1] = 0;
    404      1.2   bouyer 		scsi_pdata.blk_desc.nblocks[2] = 0;
    405      1.2   bouyer 	}
    406      1.2   bouyer 
    407      1.2   bouyer 	/*
    408      1.2   bouyer 	 * Do the command
    409      1.2   bouyer 	 */
    410      1.2   bouyer 	error = scsipi_mode_select(periph, SMS_PF, &scsi_pdata.header,
    411      1.2   bouyer 	    scsi_dlen, flags | XS_CTL_DATA_ONSTACK, ST_RETRIES, ST_CTL_TIME);
    412      1.2   bouyer 
    413      1.2   bouyer 	if (error && (page & SMS_PAGE_CODE) == 0xf) {
    414      1.2   bouyer 		/*
    415      1.2   bouyer 		 * Try DEVICE CONFIGURATION page.
    416      1.2   bouyer 		 */
    417      1.2   bouyer 		page = SMS_PAGE_CTRL_CURRENT | 0x10;
    418      1.2   bouyer 		goto again;
    419      1.2   bouyer 	}
    420      1.2   bouyer 	return (error);
    421      1.1   bouyer }
    422