1 .\" gsc.4 - manual page for the scanner device driver `gsc'
4 .\" Copyright (c) 1995 Gunther Schadow. All rights reserved.
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31 .\" $FreeBSD: src/share/man/man4/man4.i386/gsc.4,v 1.12.2.7 2001/12/17 11:30:13 ru Exp $
32 .\" $DragonFly: src/share/man/man4/man4.i386/gsc.4,v 1.4 2007/05/17 08:19:01 swildner Exp $
39 .Nd a device driver for a handy scanner
43 .Cd Minor number bits: Ar uu d g p ...
44 .Bl -tag -width "uu " -compact -offset indent
67 character device driver currently handles only the
68 Genius GS-4500 handy scanner.
69 It operates in pure DMA modes, although
70 the hardware could be set up to work with irq.
72 documentation nor experience in writing interrupt driven device
75 The device can operate at four different
79 It produces a simple bitmap with the most significant
81 The driver can optionally output the famous and
82 likely simple portable bitmap file format
85 Thus the scans can easily processed by any graphic package around
90 only to name some of them ...). In
93 bit which is set means a black pixel because the scanner detects black
94 points on white paper.
95 On the other hand, because pnm format describes
96 intensities of electron beams in video screens a set bit in
98 mode means a white pixel.
102 of the output bitmap is fixed as given by the
106 of the bitmap must be
109 mode since the driver must know at what time the
112 With this feature you are able to
113 directly copy the scanner output into a pbm file with
115 Of course you can obtain a similar effect by using
123 output mode is not yet implemented into the driver.
124 It is even questionable if external programs would not do this job
125 better thereby not counting to the size of the kernel.
127 do not know of tools which produce a graymap from a halftone bitmap.
129 The ioctl requests that are served by
132 There is a utility, called
134 that provides access to these
135 requests from within shell.
141 If this call is made after the first
142 read access to the device there will be no effect unless the device is
143 closed and opened again.
145 Get current resolution in dots per inch (dpi).
147 Set resolution value from selector switch.
148 The driver must be in an
149 open though untouched state otherwise the request will fail and
157 Actually, this is an alternative
158 way of setting the resolution, since any allowed resolution matches
160 Allowed are listed in the table below.
161 .Bl -tag -width resolution -compact -offset indent
180 Values which are not reported in the above table will cause the ioctl
186 As you can see, there are width values > 1696.
187 This does, however, not
188 mean that you can obtain scanned lines longer than the width of your
189 scanner or by higher resolutions.
190 Actually, the resolution is selected
191 by only by the hardware switch.
192 Any line that is longer than what is
193 defined for the actual resolution will be undefined (usually white) on
194 the right part that is exceeding the standard line.
196 Get current width of the bitmap in pixels.
204 a limit on the amount of lines scannable after the first read
206 When the limit is reached read will return 0. However, the
207 device is turned off only when a close is performed (either
208 explicitly or implicitly on exit of the calling process).
210 Get the current height of the bitmap.
212 Set the length of the buffer used internally to do the DMA transfer.
213 The buffer length is supplied in lines of the bitmap.
215 size limit is (currently) 0x3000 bytes the maximum number of lines
216 allowed will vary with the width of each line.
218 checked before it overwrites the current value and passes an
223 However, since the bitmap width can change
224 after a buffer length was selected a read request may fail with
226 if the buffer length turns out too high.
227 It is generally wise to
228 choose long buffers rather than go save in order to obtain better
231 Get the current buffer length in lines.
233 Set the timeout for the completion of reading one buffer.
235 handy scanner is a human/computer interface timeout values are usually
236 higher than those of a flat scanner.
237 Default is 15 seconds.
239 timeout is reached the read operation will fail with
242 the timeout timer starts anew for each buffer to be read and thus does
243 not cause you to scan faster for longer images.
244 BLEN/BTIME is similar
248 Get the current buffer timeout.
251 All ioctl requests that modify a parameter except GSC_SBTIME do not
252 have an effect on an ongoing scan process, i.e. after the first read
253 request that follows open.
254 You must close the device and open it again
255 for the new selections to take effect.
256 Consequently, the selections
257 are not reset when you close or open the device.
259 Similarly, requests that read a value do not report the value that is
260 used for the ongoing scan process.
261 The values needed during the scan
262 process are saved when it starts and thus are not accessed by ioctl
265 The BTIME value does, however, have an immediate effect on the ongoing
267 Thus the timeout can for example be set to long until the user
268 starts scanning. It can then be set to a short amount to react
269 (nearly) immediately when the user stops.
270 Note that the user should be
271 left time to at least fill one buffer without having to haste.
277 mode selection is done by the
278 minor number not by ioctl requests.
282 height of the bitmap will have no effect.
284 .Bl -tag -width /dev/gsc0pd
288 output, has minor number 0.
295 GSCDEBUG option was given at compile time, has minor number 32.
297 device node for output in
299 file format, has minor number 8.
305 mode, has minor number 40.
308 .Bd -literal -offset indent
309 dd if=/dev/gsc0 of=rawfile bs=(width/8) count=(height)
311 cat /dev/gsc0p > pbmfile
316 When you define this name as an `option' in the kernel configuration
317 you can get debug output if you access the driver with a minor number
318 whose debug bit (i.e. bit 5 out of 7) is set.
334 .An Gunther Schadow Aq gusw@fub46.zedat.fu-berlin.de
336 Even though the scanner device has a little switch by which you should
337 be able to select one of the four resolution modes, I could not yet
338 determine how to read its status.
339 Unless this is not fixed the driver
340 depends on the value passed by means of
343 what is selected by the hardware.