1 Parport
2 +++++++
3
4 The ``parport`` code provides parallel-port su
5 includes the ability to share one port between
6 drivers.
7
8 You can pass parameters to the ``parport`` cod
9 detection of your hardware. This is particula
10 to use IRQs, since in general these can't be a
11 By default IRQs are not used even if they **ca
12 because there are a lot of people using the sa
13 parallel port and a sound card or network card
14
15 The ``parport`` code is split into two parts:
16 port-sharing) and architecture-dependent (whic
17 using the port).
18
19
20 Parport as modules
21 ==================
22
23 If you load the `parport`` code as a module, s
24
25 # insmod parport
26
27 to load the generic ``parport`` code. You the
28 architecture-dependent code with (for example)
29
30 # insmod parport_pc io=0x3bc,0x378,0x2
31
32 to tell the ``parport`` code that you want thr
33 0x3bc with no IRQ, one at 0x378 using IRQ 7, a
34 auto-detected IRQ. Currently, PC-style (``par
35 Amiga, Atari, and MFC3 hardware is supported.
36
37 PCI parallel I/O card support comes from ``par
38 addresses should not be specified for supporte
39 are automatically detected.
40
41
42 modprobe
43 --------
44
45 If you use modprobe , you will find it useful
46 configuration file in /etc/modprobe.d/ directo
47
48 alias parport_lowlevel parport_pc
49 options parport_pc io=0x378,0x278 irq=
50
51 modprobe will load ``parport_pc`` (with the op
52 whenever a parallel port device driver (such a
53
54 Note that these are example lines only! You s
55 to specify any options to ``parport_pc`` in or
56 parallel port.
57
58
59 Parport probe [optional]
60 ------------------------
61
62 In 2.2 kernels there was a module called ``par
63 for collecting IEEE 1284 device ID information
64 enhanced and now lives with the IEEE 1284 supp
65 port is detected, the devices that are connect
66 and information is logged like this::
67
68 parport0: Printer, BJC-210 (Canon)
69
70 The probe information is available from files
71
72
73 Parport linked into the kernel statically
74 =========================================
75
76 If you compile the ``parport`` code into the k
77 kernel boot parameters to get the same effect.
78 following to your LILO command line::
79
80 parport=0x3bc parport=0x378,7 parport=
81
82 You can have many ``parport=...`` statements,
83 to add. Adding ``parport=0`` to the kernel co
84 parport support entirely. Adding ``parport=au
85 command-line will make ``parport`` use any IRQ
86 it auto-detects.
87
88
89 Files in /proc
90 ==============
91
92 If you have configured the ``/proc`` filesyste
93 see a new directory entry: ``/proc/sys/dev/par
94 directory entry for each parallel port for whi
95 configured. In each of those directories are
96 describing that parallel port.
97
98 The ``/proc/sys/dev/parport`` directory tree l
99
100 parport
101 |-- default
102 | |-- spintime
103 | `-- timeslice
104 |-- parport0
105 | |-- autoprobe
106 | |-- autoprobe0
107 | |-- autoprobe1
108 | |-- autoprobe2
109 | |-- autoprobe3
110 | |-- devices
111 | | |-- active
112 | | `-- lp
113 | | `-- timeslice
114 | |-- base-addr
115 | |-- irq
116 | |-- dma
117 | |-- modes
118 | `-- spintime
119 `-- parport1
120 |-- autoprobe
121 |-- autoprobe0
122 |-- autoprobe1
123 |-- autoprobe2
124 |-- autoprobe3
125 |-- devices
126 | |-- active
127 | `-- ppa
128 | `-- timeslice
129 |-- base-addr
130 |-- irq
131 |-- dma
132 |-- modes
133 `-- spintime
134
135 .. tabularcolumns:: |p{4.0cm}|p{13.5cm}|
136
137 ======================= ======================
138 File Contents
139 ======================= ======================
140 ``devices/active`` A list of the device d
141 will appear by the nam
142 the port (it might not
143 string "none" means th
144 using that port.
145
146 ``base-addr`` Parallel port's base a
147 has more than one in w
148 with tabs. These valu
149 meaning for some ports
150
151 ``irq`` Parallel port's IRQ, o
152
153 ``dma`` Parallel port's DMA ch
154 used.
155
156 ``modes`` Parallel port's hardwa
157 meaning:
158
159 - PCSPP
160 PC-style SPP r
161
162 - TRISTATE
163 Port is bidire
164
165 - COMPAT
166 Hardware accel
167 available and
168
169 - EPP
170 Hardware accel
171 is available a
172
173 - ECP
174 Hardware accel
175 is available a
176
177 - DMA
178 DMA is availab
179
180 Note that the current
181 advantage of COMPAT an
182 line to use.
183
184 ``autoprobe`` Any IEEE-1284 device I
185 acquired from the (non
186
187 ``autoprobe[0-3]`` IEEE 1284 device ID in
188 daisy-chain devices th
189
190 ``spintime`` The number of microsec
191 for the peripheral to
192 adjusting this improve
193 peripherals. This is
194 applies to all devices
195
196 ``timeslice`` The number of millisec
197 allowed to keep a port
198 and driver can ignore
199
200 ``default/*`` The defaults for spint
201 port is registered, it
202 When a new device is r
203 default timeslice.
204 ======================= ======================
205
206 Device drivers
207 ==============
208
209 Once the parport code is initialised, you can
210 specific ports. Normally this happens automat
211 is loaded it will create one lp device for eac
212 override this, though, by using parameters eit
213 driver::
214
215 # insmod lp parport=0,2
216
217 or on the LILO command line::
218
219 lp=parport0 lp=parport2
220
221 Both the above examples would inform lp that y
222 the first parallel port, and /dev/lp1 to be th
223 with no lp device associated with the second p
224 that this is different to the way older kernel
225 be a static association between the I/O port a
226 name, so ``/dev/lp0`` was always the port at 0
227 case - if you only have one port, it will defa
228 regardless of base address.
229
230 Also:
231
232 * If you selected the IEEE 1284 support at co
233 ``lp=auto`` on the kernel command line, and
234 only for those ports that seem to have prin
235
236 * If you give PLIP the ``timid`` parameter, e
237 the command line, or with ``insmod plip tim
238 it will avoid any ports that seem to be in
239
240 * IRQ autoprobing works only for a few port t
241
242 Reporting printer problems with parport
243 =======================================
244
245 If you are having problems printing, please go
246 try to narrow down where the problem area is.
247
248 When reporting problems with parport, really y
249 the messages that ``parport_pc`` spits out whe
250 several code paths:
251
252 - polling
253 - interrupt-driven, protocol in software
254 - interrupt-driven, protocol in hardware using
255 - interrupt-driven, protocol in hardware using
256
257 The kernel messages that ``parport_pc`` logs g
258 code path is being used. (They could be a lot
259
260 For normal printer protocol, having IEEE 1284
261 should not make a difference.
262
263 To turn off the 'protocol in hardware' code pa
264 ``CONFIG_PARPORT_PC_FIFO``. Note that when th
265 necessarily **used**; it depends on whether th
266 enabled by the BIOS, and detected by the drive
267
268 So, to start with, disable ``CONFIG_PARPORT_PC
269 with ``irq=none``. See if printing works then.
270 because this is the simplest code path.
271
272 If that works fine, try with ``io=0x378 irq=7`
273 hardware), to make it use interrupt-driven in-
274
275 If **that** works fine, then one of the hardwa
276 right. Enable ``CONFIG_FIFO`` (no, it isn't a
277 and yes, it should be), set the port to ECP mo
278 the DMA channel, and try with::
279
280 io=0x378 irq=7 dma=none (for PIO)
281 io=0x378 irq=7 dma=3 (for DMA)
282
283 ----------
284
285 philb@gnu.org
286 tim@cyberelk.net
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