Merge branch 'release/experimental/1.0.29-1_experimental1'experimental/1.0.29-1_experimental1

1 files changed, 972 insertions, 0 deletions

diff --git a/backend/pixma/pixma_mp750.c b/backend/pixma/pixma_mp750.c
new file mode 100644
index 0000000..7f00023
--- /dev/null
+++ b/backend/pixma/pixma_mp750.c
@@ -0,0 +1,972 @@
+/* SANE - Scanner Access Now Easy.
+
+   Copyright (C) 2011-2019 Rolf Bensch <rolf at bensch hyphen online dot de>
+   Copyright (C) 2006-2007 Wittawat Yamwong <wittawat@web.de>
+
+   This file is part of the SANE package.
+
+   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 2 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.
+
+   As a special exception, the authors of SANE give permission for
+   additional uses of the libraries contained in this release of SANE.
+
+   The exception is that, if you link a SANE library with other files
+   to produce an executable, this does not by itself cause the
+   resulting executable to be covered by the GNU General Public
+   License.  Your use of that executable is in no way restricted on
+   account of linking the SANE library code into it.
+
+   This exception does not, however, invalidate any other reasons why
+   the executable file might be covered by the GNU General Public
+   License.
+
+   If you submit changes to SANE to the maintainers to be included in
+   a subsequent release, you agree by submitting the changes that
+   those changes may be distributed with this exception intact.
+
+   If you write modifications of your own for SANE, it is your choice
+   whether to permit this exception to apply to your modifications.
+   If you do not wish that, delete this exception notice.
+ */
+
+/****************************************************************************
+ * Credits should go to Martin Schewe (http://pixma.schewe.com) who analysed
+ * the protocol of MP750.
+ ****************************************************************************/
+
+#include "../include/sane/config.h"
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "pixma_rename.h"
+#include "pixma_common.h"
+#include "pixma_io.h"
+
+/* TODO: remove lines marked with SIM. They are inserted so that I can test
+   the subdriver with the simulator. WY */
+
+#ifdef __GNUC__
+# define UNUSED(v) (void) v
+#else
+# define UNUSED(v)
+#endif
+
+#define IMAGE_BLOCK_SIZE 0xc000
+#define CMDBUF_SIZE 512
+#define HAS_PAPER(s) (s[1] == 0)
+#define IS_WARMING_UP(s) (s[7] != 3)
+#define IS_CALIBRATED(s) (s[8] == 0xf)
+
+#define MP750_PID 0x1706
+#define MP760_PID 0x1708
+#define MP780_PID 0x1707
+
+
+enum mp750_state_t
+{
+  state_idle,
+  state_warmup,
+  state_scanning,
+  state_transfering,
+  state_finished
+};
+
+enum mp750_cmd_t
+{
+  cmd_start_session = 0xdb20,
+  cmd_select_source = 0xdd20,
+  cmd_scan_param = 0xde20,
+  cmd_status = 0xf320,
+  cmd_abort_session = 0xef20,
+  cmd_time = 0xeb80,
+  cmd_read_image = 0xd420,
+
+  cmd_activate = 0xcf60,
+  cmd_calibrate = 0xe920,
+  cmd_error_info = 0xff20
+};
+
+typedef struct mp750_t
+{
+  enum mp750_state_t state;
+  pixma_cmdbuf_t cb;
+  unsigned raw_width, raw_height;
+  uint8_t current_status[12];
+
+  uint8_t *buf, *rawimg, *img;
+  /* make new buffer for rgb_to_gray to act on */
+  uint8_t *imgcol;
+  unsigned line_size; /* need in 2 functions */
+
+  unsigned rawimg_left, imgbuf_len, last_block_size, imgbuf_ofs;
+  int shifted_bytes;
+  int stripe_shift; /* for 2400dpi */
+  unsigned last_block;
+
+  unsigned monochrome:1;
+  unsigned needs_abort:1;
+} mp750_t;
+
+
+
+static void mp750_finish_scan (pixma_t * s);
+static void check_status (pixma_t * s);
+
+static int
+has_paper (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return HAS_PAPER (mp->current_status);
+}
+
+static int
+is_warming_up (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return IS_WARMING_UP (mp->current_status);
+}
+
+static int
+is_calibrated (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return IS_CALIBRATED (mp->current_status);
+}
+
+static void
+drain_bulk_in (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  while (pixma_read (s->io, mp->buf, IMAGE_BLOCK_SIZE) >= 0);
+}
+
+static int
+abort_session (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return pixma_exec_short_cmd (s, &mp->cb, cmd_abort_session);
+}
+
+static int
+query_status (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  uint8_t *data;
+  int error;
+
+  data = pixma_newcmd (&mp->cb, cmd_status, 0, 12);
+  error = pixma_exec (s, &mp->cb);
+  if (error >= 0)
+    {
+      memcpy (mp->current_status, data, 12);
+      PDBG (pixma_dbg (3, "Current status: paper=%u cal=%u lamp=%u\n",
+		       data[1], data[8], data[7]));
+    }
+  return error;
+}
+
+static int
+activate (pixma_t * s, uint8_t x)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  uint8_t *data = pixma_newcmd (&mp->cb, cmd_activate, 10, 0);
+  data[0] = 1;
+  data[3] = x;
+  return pixma_exec (s, &mp->cb);
+}
+
+static int
+activate_cs (pixma_t * s, uint8_t x)
+{
+   /*SIM*/ check_status (s);
+  return activate (s, x);
+}
+
+static int
+start_session (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return pixma_exec_short_cmd (s, &mp->cb, cmd_start_session);
+}
+
+static int
+select_source (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  uint8_t *data = pixma_newcmd (&mp->cb, cmd_select_source, 10, 0);
+  data[0] = (s->param->source == PIXMA_SOURCE_ADF) ? 2 : 1;
+  data[1] = 1;
+  return pixma_exec (s, &mp->cb);
+}
+
+static int
+has_ccd_sensor (pixma_t * s)
+{
+  return ((s->cfg->cap & PIXMA_CAP_CCD) != 0);
+}
+
+static int
+is_ccd_grayscale (pixma_t * s)
+{
+  return (has_ccd_sensor (s) && (s->param->channels == 1));
+}
+
+/* CCD sensors don't have a Grayscale mode, but use color mode instead */
+static unsigned
+get_cis_ccd_line_size (pixma_t * s)
+{
+  return (s->param->wx ? s->param->line_size / s->param->w * s->param->wx
+	  : s->param->line_size) * ((is_ccd_grayscale (s)) ? 3 : 1);
+}
+
+static int
+send_scan_param (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  uint8_t *data;
+
+  data = pixma_newcmd (&mp->cb, cmd_scan_param, 0x2e, 0);
+  pixma_set_be16 (s->param->xdpi | 0x8000, data + 0x04);
+  pixma_set_be16 (s->param->ydpi | 0x8000, data + 0x06);
+  pixma_set_be32 (s->param->x, data + 0x08);
+  pixma_set_be32 (s->param->y, data + 0x0c);
+  pixma_set_be32 (mp->raw_width, data + 0x10);
+  pixma_set_be32 (mp->raw_height, data + 0x14);
+  data[0x18] = 8;		/* 8 = color, 4 = grayscale(?) */
+  /* GH: No, there is no grayscale for CCD devices, Windows shows same  */
+  data[0x19] = s->param->depth * ((is_ccd_grayscale (s)) ? 3 : s->param->channels);	/* bits per pixel */
+  data[0x20] = 0xff;
+  data[0x23] = 0x81;
+  data[0x26] = 0x02;
+  data[0x27] = 0x01;
+  data[0x29] = mp->monochrome ? 0 : 1;
+
+  return pixma_exec (s, &mp->cb);
+}
+
+static int
+calibrate (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  return pixma_exec_short_cmd (s, &mp->cb, cmd_calibrate);
+}
+
+static int
+calibrate_cs (pixma_t * s)
+{
+   /*SIM*/ check_status (s);
+  return calibrate (s);
+}
+
+static int
+request_image_block_ex (pixma_t * s, unsigned *size, uint8_t * info,
+			unsigned flag)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  int error;
+
+  memset (mp->cb.buf, 0, 10);
+  pixma_set_be16 (cmd_read_image, mp->cb.buf);
+  mp->cb.buf[7] = *size >> 8;
+  mp->cb.buf[8] = 4 | flag;
+  mp->cb.reslen = pixma_cmd_transaction (s, mp->cb.buf, 10, mp->cb.buf, 6);
+  mp->cb.expected_reslen = 0;
+  error = pixma_check_result (&mp->cb);
+  if (error >= 0)
+    {
+      if (mp->cb.reslen == 6)
+        {
+          *info = mp->cb.buf[2];
+          *size = pixma_get_be16 (mp->cb.buf + 4);
+        }
+      else
+        {
+          error = PIXMA_EPROTO;
+        }
+    }
+  return error;
+}
+
+static int
+request_image_block (pixma_t * s, unsigned *size, uint8_t * info)
+{
+  return request_image_block_ex (s, size, info, 0);
+}
+
+static int
+request_image_block2 (pixma_t * s, uint8_t * info)
+{
+  unsigned temp = 0;
+  return request_image_block_ex (s, &temp, info, 0x20);
+}
+
+static int
+read_image_block (pixma_t * s, uint8_t * data)
+{
+  int count, temp;
+
+  count = pixma_read (s->io, data, IMAGE_BLOCK_SIZE);
+  if (count < 0)
+    return count;
+  if (count == IMAGE_BLOCK_SIZE)
+    {
+      int error = pixma_read (s->io, &temp, 0);
+      if (error < 0)
+        {
+          PDBG (pixma_dbg
+          (1, "WARNING: reading zero-length packet failed %d\n", error));
+        }
+    }
+  return count;
+}
+
+static int
+read_error_info (pixma_t * s, void *buf, unsigned size)
+{
+  unsigned len = 16;
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  uint8_t *data;
+  int error;
+
+  data = pixma_newcmd (&mp->cb, cmd_error_info, 0, len);
+  error = pixma_exec (s, &mp->cb);
+  if (error >= 0 && buf)
+    {
+      if (len < size)
+        size = len;
+      /* NOTE: I've absolutely no idea what the returned data mean. */
+      memcpy (buf, data, size);
+      error = len;
+    }
+  return error;
+}
+
+static int
+send_time (pixma_t * s)
+{
+  /* TODO: implement send_time() */
+  UNUSED (s);
+  PDBG (pixma_dbg (3, "send_time() is not yet implemented.\n"));
+  return 0;
+}
+
+static int
+handle_interrupt (pixma_t * s, int timeout)
+{
+  int error;
+  uint8_t intr[16];
+
+  error = pixma_wait_interrupt (s->io, intr, sizeof (intr), timeout);
+  if (error == PIXMA_ETIMEDOUT)
+    return 0;
+  if (error < 0)
+    return error;
+  if (error != 16)
+    {
+      PDBG (pixma_dbg (1, "WARNING: unexpected interrupt packet length %d\n",
+		       error));
+      return PIXMA_EPROTO;
+    }
+
+  if (intr[10] & 0x40)
+    send_time (s);
+  if (intr[12] & 0x40)
+    query_status (s);
+  if (intr[15] & 1)
+    s->events = PIXMA_EV_BUTTON2;	/* b/w scan */
+  if (intr[15] & 2)
+    s->events = PIXMA_EV_BUTTON1;	/* color scan */
+  return 1;
+}
+
+static void
+check_status (pixma_t * s)
+{
+  while (handle_interrupt (s, 0) > 0);
+}
+
+static int
+step1 (pixma_t * s)
+{
+  int error, tmo;
+
+  error = activate (s, 0);
+  if (error < 0)
+    return error;
+  error = query_status (s);
+  if (error < 0)
+    return error;
+  if (s->param->source == PIXMA_SOURCE_ADF && !has_paper (s))
+    return PIXMA_ENO_PAPER;
+  error = activate_cs (s, 0);
+   /*SIM*/ if (error < 0)
+    return error;
+  error = activate_cs (s, 0x20);
+  if (error < 0)
+    return error;
+
+  tmo = 60;
+  error = calibrate_cs (s);
+  while (error == PIXMA_EBUSY && --tmo >= 0)
+    {
+      if (s->cancel)
+	return PIXMA_ECANCELED;
+      PDBG (pixma_dbg
+	    (2, "Scanner is busy. Timed out in %d sec.\n", tmo + 1));
+      pixma_sleep (1000000);
+      error = calibrate_cs (s);
+    }
+  return error;
+}
+
+static void
+shift_rgb (const uint8_t * src, unsigned pixels,
+	   int sr, int sg, int sb, int stripe_shift,
+	   int line_size, uint8_t * dst)
+{
+  unsigned st;
+
+  for (; pixels != 0; pixels--)
+    {
+      st = (pixels % 2 == 0) ? -2 * stripe_shift * line_size : 0;
+      *(dst++ + sr + st) = *src++;
+      *(dst++ + sg + st) = *src++;
+      *(dst++ + sb + st) = *src++;
+    }
+}
+
+static uint8_t *
+rgb_to_gray (uint8_t * gptr, const uint8_t * cptr, unsigned pixels, unsigned c)
+{
+  unsigned i, j, g;
+
+  /* gptr: destination gray scale buffer */
+  /* cptr: source color scale buffer */
+  /* c: 3 for 3-channel single-byte data, 6 for double-byte data */
+
+  for (i=0; i < pixels; i++)
+    {
+      for (j = 0, g = 0; j < 3; j++)
+        {
+          g += *cptr++;
+	  if (c == 6) g += (*cptr++ << 8);
+        }
+      g /= 3;
+      *gptr++ = g;
+      if (c == 6) *gptr++ = (g >> 8);
+    }
+  return gptr;
+}
+
+static int
+calc_component_shifting (pixma_t * s)
+{
+  switch (s->cfg->pid)
+    {
+    case MP760_PID:
+      switch (s->param->ydpi)
+	{
+	case 300:
+	  return 3;
+	case 600:
+	  return 6;
+	default:
+	  return s->param->ydpi / 75;
+	}
+      /* never reached */
+      break;
+
+    case MP750_PID:
+    case MP780_PID:
+    default:
+      return 2 * s->param->ydpi / 75;
+    }
+}
+
+static void
+workaround_first_command (pixma_t * s)
+{
+  /* FIXME: Send a dummy command because the device doesn't response to the
+     first command that is sent directly after the USB interface has been
+     set up. Why? USB isn't set up properly? */
+  uint8_t cmd[10];
+  int error;
+
+  if (s->cfg->pid == MP750_PID)
+    return;			/* MP750 doesn't have this problem(?) */
+
+  PDBG (pixma_dbg
+	(1,
+	 "Work-around for the problem: device doesn't response to the first command.\n"));
+  memset (cmd, 0, sizeof (cmd));
+  pixma_set_be16 (cmd_calibrate, cmd);
+  error = pixma_write (s->io, cmd, 10);
+  if (error != 10)
+    {
+      if (error < 0)
+	{
+	  PDBG (pixma_dbg
+		(1, "  Sending a dummy command failed: %s\n",
+		 pixma_strerror (error)));
+	}
+      else
+	{
+	  PDBG (pixma_dbg
+		(1, "  Sending a dummy command failed: count = %d\n", error));
+	}
+      return;
+    }
+  error = pixma_read (s->io, cmd, sizeof (cmd));
+  if (error >= 0)
+    {
+      PDBG (pixma_dbg
+	    (1, "  Got %d bytes response from a dummy command.\n", error));
+    }
+  else
+    {
+      PDBG (pixma_dbg
+	    (1, "  Reading response of a dummy command failed: %s\n",
+	     pixma_strerror (error)));
+    }
+}
+
+static int
+mp750_open (pixma_t * s)
+{
+  mp750_t *mp;
+  uint8_t *buf;
+
+  mp = (mp750_t *) calloc (1, sizeof (*mp));
+  if (!mp)
+    return PIXMA_ENOMEM;
+
+  buf = (uint8_t *) malloc (CMDBUF_SIZE);
+  if (!buf)
+    {
+      free (mp);
+      return PIXMA_ENOMEM;
+    }
+
+  s->subdriver = mp;
+  mp->state = state_idle;
+
+  /* ofs:   0   1    2  3  4  5  6  7  8  9
+     cmd: cmd1 cmd2 00 00 00 00 00 00 00 00
+     data length-^^^^^    => cmd_len_field_ofs
+     |--------- cmd_header_len --------|
+
+     res: res1 res2
+     |---------| res_header_len
+   */
+  mp->cb.buf = buf;
+  mp->cb.size = CMDBUF_SIZE;
+  mp->cb.res_header_len = 2;
+  mp->cb.cmd_header_len = 10;
+  mp->cb.cmd_len_field_ofs = 7;
+
+  handle_interrupt (s, 200);
+  workaround_first_command (s);
+  return 0;
+}
+
+static void
+mp750_close (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+
+  mp750_finish_scan (s);
+  free (mp->cb.buf);
+  free (mp);
+  s->subdriver = NULL;
+}
+
+static int
+mp750_check_param (pixma_t * s, pixma_scan_param_t * sp)
+{
+  unsigned raw_width;
+
+  UNUSED (s);
+
+  sp->depth = 8;		/* FIXME: Does MP750 supports other depth? */
+
+  /* GH: my implementation */
+  /*   if ((sp->channels == 3) || (is_ccd_grayscale (s)))
+    raw_width = ALIGN_SUP (sp->w, 4);
+  else
+  raw_width = ALIGN_SUP (sp->w, 12);*/
+
+  /* the above code gives segmentation fault?!? why... it seems to work in the mp750_scan function */
+  raw_width = ALIGN_SUP (sp->w, 4);
+
+  /*sp->line_size = raw_width * sp->channels;*/
+  sp->line_size = raw_width * sp->channels * (sp->depth / 8);  /* no cropping? */
+  return 0;
+}
+
+static int
+mp750_scan (pixma_t * s)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  int error;
+  uint8_t *buf;
+  unsigned size, dpi, spare;
+
+  dpi = s->param->ydpi;
+  /* add a stripe shift for 2400dpi */
+  mp->stripe_shift = (dpi == 2400) ? 4 : 0;
+
+  if (mp->state != state_idle)
+    return PIXMA_EBUSY;
+
+  /* clear interrupt packets buffer */
+  while (handle_interrupt (s, 0) > 0)
+    {
+    }
+
+  /*  if (s->param->channels == 1)
+    mp->raw_width = ALIGN_SUP (s->param->w, 12);
+  else
+    mp->raw_width = ALIGN_SUP (s->param->w, 4);*/
+
+  /* change to use CCD grayscale mode --- why does this give segmentation error at runtime in mp750_check_param? */
+  if ((s->param->channels == 3) || (is_ccd_grayscale (s)))
+    mp->raw_width = ALIGN_SUP (s->param->w, 4);
+  else
+    mp->raw_width = ALIGN_SUP (s->param->w, 12);
+  /* not sure about MP750, but there is no need for aligning at 12 for the MP760/770, MP780/790 since always use CCD color mode */
+
+  /* modify for stripe shift */
+  spare = 2 * calc_component_shifting (s) + 2 * mp->stripe_shift; /* FIXME: or maybe (2*... + 1)? */
+  mp->raw_height = s->param->h + spare;
+  PDBG (pixma_dbg (3, "raw_width=%u raw_height=%u dpi=%u\n",
+		   mp->raw_width, mp->raw_height, dpi));
+
+  /* PDBG (pixma_dbg (4, "line_size=%"PRIu64"\n",s->param->line_size)); */
+
+  mp->line_size = get_cis_ccd_line_size (s); /* scanner hardware line_size multiplied by 3 for CCD grayscale */
+
+  size = 8 + 2 * IMAGE_BLOCK_SIZE + spare * mp->line_size;
+  buf = (uint8_t *) malloc (size);
+  if (!buf)
+    return PIXMA_ENOMEM;
+  mp->buf = buf;
+  mp->rawimg = buf;
+  mp->imgbuf_ofs = spare * mp->line_size;
+  mp->imgcol = mp->rawimg + IMAGE_BLOCK_SIZE + 8; /* added to make rgb->gray */
+  mp->img = mp->rawimg + IMAGE_BLOCK_SIZE + 8;
+  mp->imgbuf_len = IMAGE_BLOCK_SIZE + mp->imgbuf_ofs;
+  mp->rawimg_left = 0;
+  mp->last_block_size = 0;
+  mp->shifted_bytes = -(int) mp->imgbuf_ofs;
+
+  error = step1 (s);
+  if (error >= 0)
+    error = start_session (s);
+  if (error >= 0)
+    mp->state = state_warmup;
+  if (error >= 0)
+    error = select_source (s);
+  if (error >= 0)
+    error = send_scan_param (s);
+  if (error < 0)
+    {
+      mp750_finish_scan (s);
+      return error;
+    }
+  return 0;
+}
+
+
+static int
+mp750_fill_buffer (pixma_t * s, pixma_imagebuf_t * ib)
+{
+  mp750_t *mp = (mp750_t *) s->subdriver;
+  int error;
+  uint8_t info;
+  unsigned block_size, bytes_received, n;
+  int shift[3], base_shift;
+  int c;
+
+  c = ((is_ccd_grayscale (s)) ? 3 : s->param->channels) * s->param->depth / 8; /* single-byte or double-byte data */
+
+  if (mp->state == state_warmup)
+    {
+      int tmo = 60;
+
+      query_status (s);
+      check_status (s);
+ /*SIM*/ while (!is_calibrated (s) && --tmo >= 0)
+        {
+          if (s->cancel)
+            return PIXMA_ECANCELED;
+          if (handle_interrupt (s, 1000) > 0)
+            {
+              block_size = 0;
+              error = request_image_block (s, &block_size, &info);
+               /*SIM*/ if (error < 0)
+          return error;
+            }
+        }
+      if (tmo < 0)
+        {
+          PDBG (pixma_dbg (1, "WARNING: Timed out waiting for calibration\n"));
+          return PIXMA_ETIMEDOUT;
+        }
+      pixma_sleep (100000);
+      query_status (s);
+      if (is_warming_up (s) || !is_calibrated (s))
+        {
+          PDBG (pixma_dbg (1, "WARNING: Wrong status: wup=%d cal=%d\n",
+               is_warming_up (s), is_calibrated (s)));
+          return PIXMA_EPROTO;
+        }
+      block_size = 0;
+      request_image_block (s, &block_size, &info);
+       /*SIM*/ mp->state = state_scanning;
+      mp->last_block = 0;
+    }
+
+  /* TODO: Move to other place, values are constant. */
+  base_shift = calc_component_shifting (s) * mp->line_size;
+  if (s->param->source == PIXMA_SOURCE_ADF)
+    {
+      shift[0] = 0;
+      shift[1] = -base_shift;
+      shift[2] = -2 * base_shift;
+    }
+  else
+    {
+      shift[0] = -2 * base_shift;
+      shift[1] = -base_shift;
+      shift[2] = 0;
+    }
+
+  do
+    {
+      if (mp->last_block_size > 0)
+        {
+          block_size = mp->imgbuf_len - mp->last_block_size;
+          memcpy (mp->img, mp->img + mp->last_block_size, block_size);
+        }
+
+      do
+        {
+          if (s->cancel)
+            return PIXMA_ECANCELED;
+          if (mp->last_block)
+            {
+              /* end of image */
+              info = mp->last_block;
+              if (info != 0x38)
+                {
+                  query_status (s);
+                   /*SIM*/ while ((info & 0x28) != 0x28)
+                    {
+                      pixma_sleep (10000);
+                      error = request_image_block2 (s, &info);
+                      if (s->cancel)
+                        return PIXMA_ECANCELED;	/* FIXME: Is it safe to cancel here? */
+                      if (error < 0)
+                        return error;
+                    }
+                }
+              mp->needs_abort = (info != 0x38);
+              mp->last_block = info;
+              mp->state = state_finished;
+              return 0;
+            }
+
+          check_status (s);
+           /*SIM*/ while (handle_interrupt (s, 1) > 0);
+           /*SIM*/ block_size = IMAGE_BLOCK_SIZE;
+          error = request_image_block (s, &block_size, &info);
+          if (error < 0)
+            {
+              if (error == PIXMA_ECANCELED)
+                read_error_info (s, NULL, 0);
+              return error;
+            }
+          mp->last_block = info;
+          if ((info & ~0x38) != 0)
+            {
+              PDBG (pixma_dbg (1, "WARNING: Unknown info byte %x\n", info));
+            }
+          if (block_size == 0)
+            {
+              /* no image data at this moment. */
+              pixma_sleep (10000);
+            }
+        }
+      while (block_size == 0);
+
+      error = read_image_block (s, mp->rawimg + mp->rawimg_left);
+      if (error < 0)
+	{
+	  mp->state = state_transfering;
+	  return error;
+	}
+      bytes_received = error;
+      PASSERT (bytes_received == block_size);
+
+      /* TODO: simplify! */
+      mp->rawimg_left += bytes_received;
+      n = mp->rawimg_left / 3;
+      /* n = number of pixels in the buffer? */
+
+      /* Color to Grayscale converion for CCD sensor */
+      if (is_ccd_grayscale (s)) {
+	shift_rgb (mp->rawimg, n, shift[0], shift[1], shift[2], mp->stripe_shift, mp->line_size,
+		   mp->imgcol + mp->imgbuf_ofs);
+	/* dst: img, src: imgcol */
+	rgb_to_gray (mp->img, mp->imgcol, n, c); /* cropping occurs later? */
+	PDBG (pixma_dbg (4, "*fill_buffer: did grayscale conversion \n"));
+      }
+      /* Color image processing */
+      else {
+	shift_rgb (mp->rawimg, n, shift[0], shift[1], shift[2], mp->stripe_shift, mp->line_size,
+		   mp->img + mp->imgbuf_ofs);
+	PDBG (pixma_dbg (4, "*fill_buffer: no grayscale conversion---keep color \n"));
+      }
+
+      /* entering remaining unprocessed bytes after last complete pixel into mp->rawimg buffer -- no influence on mp->img */
+      n *= 3;
+      mp->shifted_bytes += n;
+      mp->rawimg_left -= n;	/* rawimg_left = 0, 1 or 2 bytes left in the buffer. */
+      mp->last_block_size = n;
+      memcpy (mp->rawimg, mp->rawimg + n, mp->rawimg_left);
+
+    }
+  while (mp->shifted_bytes <= 0);
+
+  if ((unsigned) mp->shifted_bytes < mp->last_block_size)
+    {
+      if (is_ccd_grayscale (s))
+	ib->rptr = mp->img + mp->last_block_size/3 - mp->shifted_bytes/3; /* testing---works OK */
+      else
+	ib->rptr = mp->img + mp->last_block_size - mp->shifted_bytes;
+    }
+  else
+    ib->rptr = mp->img;
+  if (is_ccd_grayscale (s))
+    ib->rend = mp->img + mp->last_block_size/3; /* testing---works OK */
+  else
+    ib->rend = mp->img + mp->last_block_size;
+  return ib->rend - ib->rptr;
+}
+
+static void
+mp750_finish_scan (pixma_t * s)
+{
+  int error;
+  mp750_t *mp = (mp750_t *) s->subdriver;
+
+  switch (mp->state)
+    {
+    case state_transfering:
+      drain_bulk_in (s);
+      /* fall through */
+    case state_scanning:
+    case state_warmup:
+      error = abort_session (s);
+      if (error == PIXMA_ECANCELED)
+	read_error_info (s, NULL, 0);
+      /* fall through */
+    case state_finished:
+      if (s->param->source == PIXMA_SOURCE_FLATBED)
+	{
+	   /*SIM*/ query_status (s);
+	  if (abort_session (s) == PIXMA_ECANCELED)
+	    {
+	      read_error_info (s, NULL, 0);
+	      query_status (s);
+	    }
+	}
+      query_status (s);
+       /*SIM*/ activate (s, 0);
+      if (mp->needs_abort)
+	{
+	  mp->needs_abort = 0;
+	  abort_session (s);
+	}
+      free (mp->buf);
+      mp->buf = mp->rawimg = NULL;
+      mp->state = state_idle;
+      /* fall through */
+    case state_idle:
+      break;
+    }
+}
+
+static void
+mp750_wait_event (pixma_t * s, int timeout)
+{
+  /* FIXME: timeout is not correct. See usbGetCompleteUrbNoIntr() for
+   * instance. */
+  while (s->events == 0 && handle_interrupt (s, timeout) > 0)
+    {
+    }
+}
+
+static int
+mp750_get_status (pixma_t * s, pixma_device_status_t * status)
+{
+  int error;
+
+  error = query_status (s);
+  if (error < 0)
+    return error;
+  status->hardware = PIXMA_HARDWARE_OK;
+  status->adf = (has_paper (s)) ? PIXMA_ADF_OK : PIXMA_ADF_NO_PAPER;
+  status->cal =
+    (is_calibrated (s)) ? PIXMA_CALIBRATION_OK : PIXMA_CALIBRATION_OFF;
+  status->lamp = (is_warming_up (s)) ? PIXMA_LAMP_WARMING_UP : PIXMA_LAMP_OK;
+  return 0;
+}
+
+
+static const pixma_scan_ops_t pixma_mp750_ops = {
+  mp750_open,
+  mp750_close,
+  mp750_scan,
+  mp750_fill_buffer,
+  mp750_finish_scan,
+  mp750_wait_event,
+  mp750_check_param,
+  mp750_get_status
+};
+
+#define DEVICE(name, model, pid, dpi, cap) {		\
+	name,                  /* name */		\
+	model,                 /* model */		\
+	0x04a9, pid,           /* vid pid */		\
+	0,                     /* iface */		\
+	&pixma_mp750_ops,      /* ops */		\
+        0,                     /* min_xdpi not used in this subdriver */ \
+	dpi, 2*(dpi),          /* xdpi, ydpi */		\
+        0, 0,                  /* adftpu_min_dpi & adftpu_max_dpi not used in this subdriver */ \
+        0, 0,                  /* tpuir_min_dpi & tpuir_max_dpi not used in this subdriver */   \
+	637, 877,              /* width, height */	\
+        PIXMA_CAP_CCD|         /* all scanners with CCD */ \
+        PIXMA_CAP_GRAY|PIXMA_CAP_EVENTS|cap \
+}
+
+const pixma_config_t pixma_mp750_devices[] = {
+  DEVICE ("Canon PIXMA MP750", "MP750", MP750_PID, 2400, PIXMA_CAP_ADF),
+  DEVICE ("Canon PIXMA MP760/770", "MP760/770", MP760_PID, 2400, PIXMA_CAP_TPU),
+  DEVICE ("Canon PIXMA MP780/790", "MP780/790", MP780_PID, 2400, PIXMA_CAP_ADF),
+  DEVICE (NULL, NULL, 0, 0, 0)
+};