selphy_print/backend_sonyupdneo.c

/*
 *   Sony UP-D series (new) Photo Printer CUPS backend -- libusb-1.0 version
 *
 *   (c) 2019 Solomon Peachy <pizza@shaftnet.org>
 *
 *   The latest version of this program can be found at:
 *
 *     http://git.shaftnet.org/cgit/selphy_print.git
 *
 *   This program is free software; you can redistribute it and/or modify it
 *   under the terms of the GNU General Public License as published by the Free
 *   Software Foundation; either version 3 of the License, or (at your option)
 *   any later version.
 *
 *   This program is distributed in the hope that it will be useful, but
 *   WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *   or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 *   for more details.
 *
 *   You should have received a copy of the GNU General Public License
 *   along with this program; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 *
 *          [http://www.gnu.org/licenses/gpl-3.0.html]
 *
 *   SPDX-License-Identifier: GPL-3.0+
 *
 */

#define BACKEND sonyupdneo_backend

#include "backend_common.h"

/* Private data structures */
struct updneo_printjob {
	uint8_t *databuf;
	int datalen;
	uint8_t *hdrbuf;
	int hdrlen;
	uint8_t *ftrbuf;
	int ftrlen;

//	int copies_offset;  // XXX eventually implement

	int copies;

	uint16_t rows;
	uint16_t cols;
};

struct updneo_ctx {
	struct libusb_device_handle *dev;
	uint8_t endp_up;
	uint8_t endp_down;
	int iface;
	int type;

	int native_bpp;

	struct marker marker;
};

/* Now for the code */
static void* updneo_init(void)
{
	struct updneo_ctx *ctx = malloc(sizeof(struct updneo_ctx));
	if (!ctx) {
		ERROR("Memory Allocation Failure!\n");
		return NULL;
	}
	memset(ctx, 0, sizeof(struct updneo_ctx));
	return ctx;
}

static int updneo_attach(void *vctx, struct libusb_device_handle *dev, int type,
			 uint8_t endp_up, uint8_t endp_down, int iface, uint8_t jobid)
{
	struct updneo_ctx *ctx = vctx;

	UNUSED(jobid);

	ctx->dev = dev;
	ctx->endp_up = endp_up;
	ctx->endp_down = endp_down;
	ctx->type = type;
	ctx->iface = iface;

	if (ctx->type == P_SONY_UPD898) {
		ctx->marker.color = "#000000";  /* Ie black! */
		ctx->native_bpp = 1;
	} else {
		ctx->marker.color = "#00FFFF#FF00FF#FFFF00";
		ctx->native_bpp = 3;
	}

	ctx->marker.name = "Unknown";
	ctx->marker.numtype = -1;
	ctx->marker.levelmax = -1;
	ctx->marker.levelnow = -2;

	return CUPS_BACKEND_OK;
}

static void updneo_cleanup_job(const void *vjob)
{
	const struct updneo_printjob *job = vjob;

	if (job->databuf)
		free(job->databuf);
	if (job->hdrbuf)
		free(job->hdrbuf);
	if (job->ftrbuf)
		free(job->ftrbuf);

	free((void*)job);
}

#define MAX_PRINTJOB_LEN (3400*2392*3 + 2048)

static int updneo_read_parse(void *vctx, const void **vjob, int data_fd, int copies) {
	struct updneo_ctx *ctx = vctx;
	int run = 1;

	uint8_t tmpbuf[257];

	struct updneo_printjob *job = NULL;

	if (!ctx)
		return CUPS_BACKEND_FAILED;

	/* Allocate job */
	job = malloc(sizeof(*job));
	if (!job) {
		ERROR("Memory allocation failure!\n");
		return CUPS_BACKEND_RETRY_CURRENT;
	}
	memset(job, 0, sizeof(*job));

	/* Read in data chunks. */
	while(run) {
		uint8_t *ptr = NULL;
		int i, len, *lenptr;

		/* Read in data block header (256 bytes) */
		i = read(data_fd, tmpbuf, 256);
		if (i < 0) {
			updneo_cleanup_job(job);
			return CUPS_BACKEND_CANCEL;
		}
		if (i == 0)
			break;

		/* Explicitly null terminate just in case */
		tmpbuf[256] = 0;

		/* Parse header.  Format:

		   JOBSIZE=pdlname,blocklen,printsize,arg1,..,argN<NULL>

		*/

		if (strncmp("JOBSIZE=", (char*) tmpbuf, 8)) {
			updneo_cleanup_job(job);
			ERROR("Invalid spool format!\n");
			return CUPS_BACKEND_CANCEL;
		}

		/* PDL type */
		char *tok = strtok((char*)&tmpbuf[8], "\r\n,");
		if (!tok) {
			updneo_cleanup_job(job);
			ERROR("Invalid spool format (PDL)!\n");
			return CUPS_BACKEND_CANCEL;
		}

		/* Payload length */
		char *tokl = strtok(NULL, "\r\n,");
		if (!tokl) {
			updneo_cleanup_job(job);
			ERROR("Invalid spool format (block length missing)!\n");
			return CUPS_BACKEND_CANCEL;
		}
		len = atoi(tokl);
		if (len == 0 || len > MAX_PRINTJOB_LEN) {
			updneo_cleanup_job(job);
			ERROR("Invalid spool format (block length %d)!\n", len);
			return CUPS_BACKEND_CANCEL;
		}

		/* Behavior based on the various PDL blocks */
		if (!strncmp("PJL-H", tok, 5)) {
			job->hdrbuf = malloc(len);
			if (!job->hdrbuf) {
				ERROR("Memory allocation failure!\n");
				updneo_cleanup_job(job);
				return CUPS_BACKEND_RETRY_CURRENT;
			}
			ptr = job->hdrbuf;
			lenptr = &job->hdrlen;
		} else if (!strncmp("PJL-T", tok, 5)) {
			job->ftrbuf = malloc(len);
			if (!job->ftrbuf) {
				ERROR("Memory allocation failure!\n");
				updneo_cleanup_job(job);
				return CUPS_BACKEND_RETRY_CURRENT;
			}
			ptr = job->ftrbuf;
			lenptr = &job->ftrlen;
			run = 0;
		} else if (!strncmp("PDL", tok, 3)) {
			job->databuf = malloc(len);
			if (!job->databuf) {
				ERROR("Memory allocation failure!\n");
				updneo_cleanup_job(job);
				return CUPS_BACKEND_RETRY_CURRENT;
			}
			ptr = job->databuf;
			lenptr = &job->datalen;
		} else {
			ERROR("Unrecognized PDL type '%s'\n", tok);
			updneo_cleanup_job(job);
			return CUPS_BACKEND_CANCEL;
		}

//		DEBUG("Read block '%s' @ %d ...\n", tok, job->datalen);

//		DEBUG("...len '%d'\n", len);

		// parse the rest?
		// 898MD: 6,0,0,0
		// D80MD: 4
		// CR20L: 64,0,0,0

		/* Read in the data chunk */
		while(len > 0) {
			i = read(data_fd, ptr + *lenptr, len);
			if (i < 0) {
				updneo_cleanup_job(job);
				return CUPS_BACKEND_CANCEL;
			}
			if (i == 0)
				break;

			*lenptr += i;
			len -= i;
		}
	}

	if (!job->datalen || !job->hdrlen || !job->ftrlen) {
		ERROR("Necessary block missing!\n");
		updneo_cleanup_job(job);
		return CUPS_BACKEND_CANCEL;
	}

	/* Sanity check job parameters */
	// rows * cols lines up with imgsize, and others?

	// set job copies to max(job, parameter)
	// job->copies = copies;
	job->copies = 1;  /* Printer makes copies */
	UNUSED(copies);

	*vjob = job;

	return CUPS_BACKEND_OK;
}

static int dlen;
static struct deviceid_dict dict[MAX_DICT];

static int updneo_get_status(struct updneo_ctx *ctx)
{
	char *ieee_id = get_device_id(ctx->dev, ctx->iface);

	if (!ieee_id)
		return CUPS_BACKEND_FAILED;

	dlen = parse1284_data(ieee_id, dict);

	// pull out what we care about..

	/* Clean up */
	if (ieee_id) free(ieee_id);
	while (dlen--) {
		free (dict[dlen].key);
		free (dict[dlen].val);
	}
}

static int updneo_main_loop(void *vctx, const void *vjob) {
	struct updneo_ctx *ctx = vctx;
	int ret;
	int copies;

	const struct updneo_printjob *job = vjob;

	if (!ctx)
		return CUPS_BACKEND_FAILED;
	if (!job)
		return CUPS_BACKEND_FAILED;

	copies = job->copies;

top:

	// Query printer status
	// Sanity check job parameters vs printer status
	// Check for idle


	/* Send over header */
	if ((ret = send_data(ctx->dev, ctx->endp_down,
			     job->hdrbuf, job->hdrlen)))
		return CUPS_BACKEND_FAILED;

	/* Send over data */
	if ((ret = send_data(ctx->dev, ctx->endp_down,
			     job->databuf, job->datalen)))
		return CUPS_BACKEND_FAILED;

	/* Send over footer */
	if ((ret = send_data(ctx->dev, ctx->endp_down,
			     job->ftrbuf, job->ftrlen)))
		return CUPS_BACKEND_FAILED;

	/* Wait for completion! */
retry:
	sleep(1);

	// Check for idle
	if (fast_return /*&& ctx->stsbuf.printing > 0 */) {
		INFO("Fast return mode enabled.\n");
	} else {
		goto retry;
	}

	/* Clean up */
	if (terminate)
		copies = 1;

// done:
	INFO("Print complete (%d copies remaining)\n", copies - 1);

	if (copies && --copies) {
		goto top;
	}

	return CUPS_BACKEND_OK;
}

static int updneo_cmdline_arg(void *vctx, int argc, char **argv)
{
	struct updneo_ctx *ctx = vctx;
	int i, j = 0;

	if (!ctx)
		return -1;

	while ((i = getopt(argc, argv, GETOPT_LIST_GLOBAL "s")) >= 0) {
		switch(i) {
		GETOPT_PROCESS_GLOBAL
		}

		if (j) return j;
	}

	return 0;
}

static int updneo_query_markers(void *vctx, struct marker **markers, int *count)
{
	struct updneo_ctx *ctx = vctx;

	*markers = &ctx->marker;
	*count = 1;

	// Do something?

	return CUPS_BACKEND_OK;
}

static const char *sonyupdneo_prefixes[] = {
	"sonyupdneo",
	"sony-upd898", "sony-upcr20l", "sony-updr80", "sony-updr80md",
	"dnp-sl20",
	NULL
};

/* Exported */
#define USB_VID_SONY         0x054C
#define USB_PID_SONY_UPD898MD 0xabcd // 0x589a?
#define USB_PID_SONY_UPCR20L  0xbcde
#define USB_PID_SONY_UPDR80MD 0x03c3
#define USB_PID_SONY_UPDR80   0x03c5
#define USB_PID_SONY_UPCX1    0x02d4

struct dyesub_backend sonyupdneo_backend = {
	.name = "Sony UP-D Neo",
	.version = "0.03WIP",
	.uri_prefixes = sonyupdneo_prefixes,
	.cmdline_arg = updneo_cmdline_arg,
	.init = updneo_init,
	.attach = updneo_attach,
	.cleanup_job = updneo_cleanup_job,
	.read_parse = updneo_read_parse,
	.main_loop = updneo_main_loop,
	.query_markers = updneo_query_markers,
	.devices = {
		{ USB_VID_SONY, USB_PID_SONY_UPD898MD, P_SONY_UPD898, NULL, "sony-upd898"},
		{ USB_VID_SONY, USB_PID_SONY_UPCR20L, P_SONY_UPCR20L, NULL, "sony-upcr20l"},
		{ USB_VID_SONY, USB_PID_SONY_UPDR80, P_SONY_UPDR80, NULL, "sony-updr80"},
		{ USB_VID_SONY, USB_PID_SONY_UPDR80MD, P_SONY_UPDR80, NULL, "sony-updr80md"},

		{ 0, 0, 0, NULL, NULL}
	}
};

/* Sony UP-D (new) printer spool format

   Covers UP-CR20L, UP-DR80/DR80MD, UP-D898/UP-X898

  HP-PJL wrapper around custom Sony PDL:

    JOBSIZE=PJL-H,size,arg1,arg2,etc   [null terminated, padded to 256 bytes]
    [ size bytes of PJL header! ]
    JOBSIZE=PDL,size,args [null terminated, padded to 256 bytes]
    [ size bytes of PDL data! ]
    JOBSIZE=PJL-T,size,args [null terminated, padded to 256 bytes]
    [ size bytes of PJL trailer! ]

  PJL header:

   <ESC>%-12345X<CR><LF>
   @PJL COMMENT free form text here <CR><LF>
   @PJL JOB NAME="name me" ID="someid"<CR><LF>
   @PJL .... <CR><LF>
   @PJL ENTER LANGUAGE=SONY-PDL-DS2<CR><LF>

  PJL footer:

   @PJL EOJ<CR><LF>
   <ESC>%-12345X<CR><LF>

  PDL notes:

   size is the length mentioned in the payload (ie rows * cols * planes)
   plus the PDL header (varies) and PDL footer (7 bytes)


 UP-D898MD:  18*16+2 == 290 byte header

  00000250                                             00 00   YY YY = rows
  00000260  01 00 00 10 0f 00 1c 00  00 00 00 00 00 00 00 00   XX XX = columns (fixed at 05 00)
  00000270  00 00 00 00 00 01 02 00  09 00 NN 01 00 11 01 08   NN = Copies (01..?)  <-- GUESS
  00000280  00 1a 00 00 00 00 XX XX  YY YY 09 00 28 01 00 d4
  00000290  00 00 03 58 YY YY 00 00  13 01 00 04 00 80 00 23
  000002a0  00 0c 01 09 XX XX YY YY  00 00 00 00 08 ff 08 00
  000002b0  19 00 00 00 00 XX XX YY  YY 00 00 81 80 00 8f 00
  000002c0  b8 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  000002d0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  000002f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000300  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000310  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000320  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000330  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000340  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000350  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000360  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000370  00 00 00 00 00 00 00 00  00 c0 00 82 LL LL LL LL   LL == payload bytes, BE (== XX * YY * 1)

   [payload of LL bytes follows]

 UP-CR20L:   290 byte header, 330 dpi, 1210x1728/1382x2048/1728*2380/2724*2048 (L/PC/2L/2PC)

  00000250                                             00 00
  00000260  01 00 00 10 0f 00 1c 00  00 00 00 00 00 00 00 00
  00000270  00 00 01 00 00 00 02 00  16 00 00 02 00 09 00 NN   NN = Copies (01..??)
  00000280  02 00 06 01 01 03 00 1d  00 00 00 01 00 20 01 01
  00000290  00 27 40 01 00 11 01 08  00 1a 00 00 00 00 RR RR
  000002a0  CC CC 00 00 13 01 00 04  00 80 00 23 00 10 03 00   CC CC == Columns  (BE)
  000002b0  RR RR CC CC 00 00 00 00  08 08 08 ff ff ff 01 00   RR RR == Rows     (BE)
  000002c0  17 00 08 00 19 00 00 00  00 RR RR CC CC 00 00 81
  000002d0  80 00 8f 00 a4 00 00 00  00 00 00 00 00 00 00 00
  000002e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  000002f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000300  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000310  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000320  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000330  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000340  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000350  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000360  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000370  00 00 00 00 00 00 00 00  00 c0 00 82 LL LL LL LL   LL == payload bytes, BE (== RR * CC * 3)

   [payload of LL bytes follows]

 UP-DR80MD:   (19*16+8) = 312 byte header  (A4 = 3400x2392, Letter = 3192*2464)

  00000240                           00 00 01 00 00 10 0f 00
  00000250  1c 00 00 00 00 00 00 00  00 00 00 00 00 00 00 ZZ   ZZ = 0x00 (Letter) 0x56 (A4)
  00000260  02 00 16 00 01 80 00 15  00 12 55 50 44 52 38 30   SS = 0x00 (LUT0) 0xff (No LUT)
  00000270  00 00 4c 55 54 QQ 00 00  00 00 00 SS 02 00 09 00   QQ = 0x30 (LUT0) 0x2f (No LUT)
  00000280  NN 02 00 06 01 03 04 00  1d 01 00 00 05 01 00 20   NN = Copies (01...??)
  00000290  00 01 00 11 01 08 00 1a  00 00 00 00 CC CC RR RR   RR RR = Rows (BE)
  000002a0  00 00 13 01 00 04 00 80  00 23 00 10 03 00 CC CC   CC CC = Cols (BE)
  000002b0  RR RR 00 00 00 00 08 08  08 ff ff ff 01 00 17 00
  000002c0  08 00 19 00 00 00 00 CC  CC RR RR 00 00 81 80 00
  000002d0  8f 00 a6 00 00 00 00 00  00 00 00 00 00 00 00 00
  000002e0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  000002f0  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000300  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000310  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000320  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000330  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000340  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000350  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000360  00 00 00 00 00 00 00 00  00 00 00 00 00 00 00 00
  00000370  00 00 00 00 00 00 00 00  00 c0 00 82 LL LL LL LL  LL == payload, BE (== RR * CC * 3)

   [payload of LL bytes follows]

 Common sequences:

  [ D898 ]

  [00 00 01 00 00 10 0f 00  1c 00 00 00 00 00 00 00
   00 00 00 00]00 00 00 01 [02 00 09 00 NN]01 00 11
   01 08 00 1a 00 00 00 00  XX XX YY YY 09 00 28 01
   00 d4 00 00 03 58 YY YY  00 00[13 01 00 04 00 80
   00 23]00 0c 01 09 XX XX  YY YY 00 00 00 00 08 ff
  [08 00 19 00 00 00 00 XX  XX YY YY 00 00 81 80 00
   8f 00 b8]

   [ 0xb8 of 0x00 ] ... c0 00 82 LL LL LL LL

  [ CR20L ]

  [00 00 01 00 00 10 0f 00  1c 00 00 00 00 00 00 00
   00 00 00 00]01 00 00 00  02 00 16 00 00[02 00 09
   00 NN]02 00 06 01 01 03  00 1d 00 00 00*01 00 20
   01 01 00 27 40 01 00 11  01 08 00 1a 00 00 00 00
   RR RR CC CC 00 00[13 01  00 04 00 80 00 23]00 10
   03 00 RR RR CC CC 00 00  00 00 08 08 08 ff ff ff
   01 00 17 00[08 00 19 00  00 00 00 RR RR CC CC 00
   00 81 80 00 8f 00 a4]

    * 03 00 13 00 01 02   [inserted when using multicut ]

   [ 0xa4 of 0x00 ] ... c0 00 82 LL LL LL LL

  [ UP-DR80MD ]

  [00 00 01 00 00 10 0f 00  1c 00 00 00 00 00 00 00
   00 00 00 00]00 00 00 ZZ  02 00 16 00 01 80 00 15
   00 12 55 50 44 52 38 30  00 00 4c 55 54 QQ 00 00
   00 00 00 SS[02 00 09 00  NN]02 00 06 01 03 04 00
   1d 01 00 00 05 01 00 20  00 01 00 11 01 08 00 1a
   00 00 00 00 CC CC RR RR  00 00[13 01 00 04 00 80
   00 23]00 10 03 00 CC CC  RR RR 00 00 00 00 08 08
   08 ff ff ff 01 00 17 00 [08 00 19 00 00 00 00 CC
   CC RR RR 00 00 81 80 00  8f 00 a6]

   [ 0xa6 of 0x00 ] ... c0 00 82 LL LL LL LL

 *********

   02 00 09 00 NN  <- Copy count
   00 00 00 ZZ     <- Media type?

   27 54 01 00

   00 10 03 00 RR RR CC CC
   08 00 19 00 00 00 00 00 RR RR CC CC 00 00 81 80 00 8f 00 a4

 *****************

  PRINTER COMMS:

   * Strip out "JOBSIZE=" headers
   * Send PJL header
   * Send PDL payload  (every 9*256KB, do a status query..)
   * Send PJL footer

  PJL header and footer need to be sent separately.
  the PJL wrapper around the PDL block needs to be
  stripped.

  ***********

  It appears that the printer status is tacked onto the IEEE1284 string:  Examples:


    MFG:SONY;MDL:UP-DR80MD;DES:Sony UP-DR80MD;CMD:SPJL-DS,SPDL-DS;CLS:PRINTER;SCDIV:0100;SCSYV:01060000;SCSNO:0000000000089864;SCSYS:0000001000010001000100;SCMDS:00000000002C002C002C;SCPRS:0000;SCSES:0000;SCWTS:0000;SCJBS:0000;SCSYE:00;SCMDE:0000;SCMCE:00;SCJBI:0000000000000000;SCSYI:0A300E5609A00C7809A00C78012D00;SCSVI:000342000342;SCMNI:000342000342;SCCAI:00000000000000;SCGAI:0000;SCGSI:00;SCMDI:110154

    MFG:SONY;MDL:UP-DR80MD;DES:Sony UP-DR80MD;CMD:SPJL-DS,SPDL-DS;CLS:PRINTER;SCDIV:0100;SCSYV:01060000;SCSNO:0000000000089864;SCSYS:0000011000010001000000;SCMDS:00000000002C002C002C;SCPRS:0005;SCSES:0000;SCWTS:0000;SCJBS:0000;SCSYE:00;SCMDE:0000;SCMCE:00;SCJBI:0000000000000000;SCSYI:0A300E5609A00C7809A00C78012D00;SCSVI:000342000342;SCMNI:000342000342;SCCAI:00000000000000;SCGAI:0000;SCGSI:00;SCMDI:110154

    MFG:SONY;MDL:UP-DR80MD;DES:Sony UP-DR80MD;CMD:SPJL-DS,SPDL-DS;CLS:PRINTER;SCDIV:0100;SCSYV:01060000;SCSNO:0000000000089864;SCSYS:0000001000010001000100;SCMDS:00000000002B002B002B;SCPRS:0000;SCSES:0000;SCWTS:0000;SCJBS:0000;SCSYE:00;SCMDE:0000;SCMCE:00;SCJBI:0000000000000000;SCSYI:0A300E5609A00C7809A00C78012D00;SCSVI:000343000343;SCMNI:000343000343;SCCAI:00000000000000;SCGAI:0000;SCGSI:00;SCMDI:110154

Breakdown:

  SCDIV
  SCSYV
  SCSNO  # SerialNO (?)
  SCSYS  # some sort of state array? 22 fields.  b19 is 1 when data can be sent?, b5 is 1 when printer busy?, b20:21 are 64 sometimes
  SCMDS  # MeDiaStatus: five 4-value hex numbers, last three decrease in unison (remaining prints). second one is 0100/0200/0300/0600, maybe Y/M/C/O?
  SCPRS  # PRinterStatus: (0000 = idle, 0002 = printing, 0005 = data xfer?)
  SCSES
  SCWTS
  SCJBS  # some sort of job count?
  SCSYE
  SCMDE  # MeDia???
  SCJBI
  SCSYI
  SCSVI  # print counter(s)?  (XXXXXXYYYYYY, and X = Y so far.  SCSVI and SCMNI are identical so far)
  SCMNI  # print counter(s)?  (see SCSVI)
  SCCAI
  SCGAI
  SCGSI
  SCMDI  # MeDia???


 */