diff options
author | Ralf Baechle <ralf@linux-mips.org> | 1997-04-29 21:13:14 +0000 |
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committer | <ralf@linux-mips.org> | 1997-04-29 21:13:14 +0000 |
commit | 19c9bba94152148523ba0f7ef7cffe3d45656b11 (patch) | |
tree | 40b1cb534496a7f1ca0f5c314a523c69f1fee464 /Documentation/parport.txt | |
parent | 7206675c40394c78a90e74812bbdbf8cf3cca1be (diff) |
Import of Linux/MIPS 2.1.36
Diffstat (limited to 'Documentation/parport.txt')
-rw-r--r-- | Documentation/parport.txt | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/Documentation/parport.txt b/Documentation/parport.txt new file mode 100644 index 000000000..17a659e55 --- /dev/null +++ b/Documentation/parport.txt @@ -0,0 +1,59 @@ +The `parport' code provides parallel-port support under Linux. This +includes the ability to share one port between multiple device +drivers. + +You can pass parameters to the parport code to override its automatic +detection of your hardware. This is particularly useful if you want +to use IRQs, since in general these can't be autoprobed successfully. + +If you load the parport code as a module, say + + # insmod parport.o io=0x378,0x278 irq=7,5 + +to tell the parport code that you want two ports, one at 0x378 using +IRQ 7, and one at 0x278 using IRQ 5. + +If you compile the parport code into the kernel, then you can use +kernel boot parameters to get the same effect. Add something like the +following to your LILO command line: + + parport=0x378,7 parport=0x278,5 + +You can have many `parport=...' statements, one for each port you want +to add. Adding `parport=0' or just `parport=' to the command-line +will disable parport support entirely. + +Once the parport code is initialised, you can attach device drivers to +ports. Normally this happens automatically; if the lp driver is +loaded it will create one lp device for each port found. You can +override this, though, by using parameters either when you load the lp +driver: + + # insmod lp.o parport=0,2 + +or on the LILO command line: + + lp=parport0 lp=parport2 + +Both the above examples would inform lp that you want /dev/lp0 to be +the first parallel port, and /dev/lp1 to be the _third_ parallel port, +with no lp device associated with the second port (parport1). Note +that this is different to the way older kernels worked; there used to +be a static association between the I/O port address and the device +name, so /dev/lp0 was always the port at 0x3bc. This is no longer the +case - if you only have one port, it will always be /dev/lp0, +regardless of base address. + +Also: + + * If you selected the device autoprobe at compile time, you can say + `lp=auto' on the kernel command line, and lp will create devices + only for those ports that seem to have printers attached. + + * If you give PLIP the `timid' parameter, either with `plip=timid' on + the command line, or with `insmod plip timid=1' when using modules, + it will avoid any ports that seem to be in use by other devices. + + * If your BIOS allows you to engage "ECP mode", you may find that + your port's IRQ can be autoprobed, without having to specify any + parameters. |