| =================================== |
| Linux and parallel port IDE devices |
| =================================== |
| |
| PARIDE v1.03 (c) 1997-8 Grant Guenther <grant@torque.net> |
| PATA_PARPORT (c) 2023 Ondrej Zary |
| |
| 1. Introduction |
| =============== |
| |
| Owing to the simplicity and near universality of the parallel port interface |
| to personal computers, many external devices such as portable hard-disk, |
| CD-ROM, LS-120 and tape drives use the parallel port to connect to their |
| host computer. While some devices (notably scanners) use ad-hoc methods |
| to pass commands and data through the parallel port interface, most |
| external devices are actually identical to an internal model, but with |
| a parallel-port adapter chip added in. Some of the original parallel port |
| adapters were little more than mechanisms for multiplexing a SCSI bus. |
| (The Iomega PPA-3 adapter used in the ZIP drives is an example of this |
| approach). Most current designs, however, take a different approach. |
| The adapter chip reproduces a small ISA or IDE bus in the external device |
| and the communication protocol provides operations for reading and writing |
| device registers, as well as data block transfer functions. Sometimes, |
| the device being addressed via the parallel cable is a standard SCSI |
| controller like an NCR 5380. The "ditto" family of external tape |
| drives use the ISA replicator to interface a floppy disk controller, |
| which is then connected to a floppy-tape mechanism. The vast majority |
| of external parallel port devices, however, are now based on standard |
| IDE type devices, which require no intermediate controller. If one |
| were to open up a parallel port CD-ROM drive, for instance, one would |
| find a standard ATAPI CD-ROM drive, a power supply, and a single adapter |
| that interconnected a standard PC parallel port cable and a standard |
| IDE cable. It is usually possible to exchange the CD-ROM device with |
| any other device using the IDE interface. |
| |
| The document describes the support in Linux for parallel port IDE |
| devices. It does not cover parallel port SCSI devices, "ditto" tape |
| drives or scanners. Many different devices are supported by the |
| parallel port IDE subsystem, including: |
| |
| - MicroSolutions backpack CD-ROM |
| - MicroSolutions backpack PD/CD |
| - MicroSolutions backpack hard-drives |
| - MicroSolutions backpack 8000t tape drive |
| - SyQuest EZ-135, EZ-230 & SparQ drives |
| - Avatar Shark |
| - Imation Superdisk LS-120 |
| - Maxell Superdisk LS-120 |
| - FreeCom Power CD |
| - Hewlett-Packard 5GB and 8GB tape drives |
| - Hewlett-Packard 7100 and 7200 CD-RW drives |
| |
| as well as most of the clone and no-name products on the market. |
| |
| To support such a wide range of devices, pata_parport is actually structured |
| in two parts. There is a base pata_parport module which provides an interface |
| to kernel libata subsystem, registry and some common methods for accessing |
| the parallel ports. |
| |
| The second component is a set of low-level protocol drivers for each of the |
| parallel port IDE adapter chips. Thanks to the interest and encouragement of |
| Linux users from many parts of the world, support is available for almost all |
| known adapter protocols: |
| |
| ==== ====================================== ==== |
| aten ATEN EH-100 (HK) |
| bpck Microsolutions backpack (US) |
| comm DataStor (old-type) "commuter" adapter (TW) |
| dstr DataStor EP-2000 (TW) |
| epat Shuttle EPAT (UK) |
| epia Shuttle EPIA (UK) |
| fit2 FIT TD-2000 (US) |
| fit3 FIT TD-3000 (US) |
| friq Freecom IQ cable (DE) |
| frpw Freecom Power (DE) |
| kbic KingByte KBIC-951A and KBIC-971A (TW) |
| ktti KT Technology PHd adapter (SG) |
| on20 OnSpec 90c20 (US) |
| on26 OnSpec 90c26 (US) |
| ==== ====================================== ==== |
| |
| |
| 2. Using pata_parport subsystem |
| =============================== |
| |
| While configuring the Linux kernel, you may choose either to build |
| the pata_parport drivers into your kernel, or to build them as modules. |
| |
| In either case, you will need to select "Parallel port IDE device support" |
| and at least one of the parallel port communication protocols. |
| If you do not know what kind of parallel port adapter is used in your drive, |
| you could begin by checking the file names and any text files on your DOS |
| installation floppy. Alternatively, you can look at the markings on |
| the adapter chip itself. That's usually sufficient to identify the |
| correct device. |
| |
| You can actually select all the protocol modules, and allow the pata_parport |
| subsystem to try them all for you. |
| |
| For the "brand-name" products listed above, here are the protocol |
| and high-level drivers that you would use: |
| |
| ================ ============ ======== |
| Manufacturer Model Protocol |
| ================ ============ ======== |
| MicroSolutions CD-ROM bpck |
| MicroSolutions PD drive bpck |
| MicroSolutions hard-drive bpck |
| MicroSolutions 8000t tape bpck |
| SyQuest EZ, SparQ epat |
| Imation Superdisk epat |
| Maxell Superdisk friq |
| Avatar Shark epat |
| FreeCom CD-ROM frpw |
| Hewlett-Packard 5GB Tape epat |
| Hewlett-Packard 7200e (CD) epat |
| Hewlett-Packard 7200e (CD-R) epat |
| ================ ============ ======== |
| |
| All parports and all protocol drivers are probed automatically unless probe=0 |
| parameter is used. So just "modprobe epat" is enough for a Imation SuperDisk |
| drive to work. |
| |
| Manual device creation:: |
| |
| # echo "port protocol mode unit delay" >/sys/bus/pata_parport/new_device |
| |
| where: |
| |
| ======== ================================================ |
| port parport name (or "auto" for all parports) |
| protocol protocol name (or "auto" for all protocols) |
| mode mode number (protocol-specific) or -1 for probe |
| unit unit number (for backpack only, see below) |
| delay I/O delay (see troubleshooting section below) |
| ======== ================================================ |
| |
| If you happen to be using a MicroSolutions backpack device, you will |
| also need to know the unit ID number for each drive. This is usually |
| the last two digits of the drive's serial number (but read MicroSolutions' |
| documentation about this). |
| |
| If you omit the parameters from the end, defaults will be used, e.g.: |
| |
| Probe all parports with all protocols:: |
| |
| # echo auto >/sys/bus/pata_parport/new_device |
| |
| Probe parport0 using protocol epat and mode 4 (EPP-16):: |
| |
| # echo "parport0 epat 4" >/sys/bus/pata_parport/new_device |
| |
| Probe parport0 using all protocols:: |
| |
| # echo "parport0 auto" >/sys/bus/pata_parport/new_device |
| |
| Probe all parports using protoocol epat:: |
| |
| # echo "auto epat" >/sys/bus/pata_parport/new_device |
| |
| Deleting devices:: |
| |
| # echo pata_parport.0 >/sys/bus/pata_parport/delete_device |
| |
| |
| 3. Troubleshooting |
| ================== |
| |
| 3.1 Use EPP mode if you can |
| ---------------------------- |
| |
| The most common problems that people report with the pata_parport drivers |
| concern the parallel port CMOS settings. At this time, none of the |
| protocol modules support ECP mode, or any ECP combination modes. |
| If you are able to do so, please set your parallel port into EPP mode |
| using your CMOS setup procedure. |
| |
| 3.2 Check the port delay |
| ------------------------- |
| |
| Some parallel ports cannot reliably transfer data at full speed. To |
| offset the errors, the protocol modules introduce a "port |
| delay" between each access to the i/o ports. Each protocol sets |
| a default value for this delay. In most cases, the user can override |
| the default and set it to 0 - resulting in somewhat higher transfer |
| rates. In some rare cases (especially with older 486 systems) the |
| default delays are not long enough. if you experience corrupt data |
| transfers, or unexpected failures, you may wish to increase the |
| port delay. |
| |
| 3.3 Some drives need a printer reset |
| ------------------------------------- |
| |
| There appear to be a number of "noname" external drives on the market |
| that do not always power up correctly. We have noticed this with some |
| drives based on OnSpec and older Freecom adapters. In these rare cases, |
| the adapter can often be reinitialised by issuing a "printer reset" on |
| the parallel port. As the reset operation is potentially disruptive in |
| multiple device environments, the pata_parport drivers will not do it |
| automatically. You can however, force a printer reset by doing:: |
| |
| insmod lp reset=1 |
| rmmod lp |
| |
| If you have one of these marginal cases, you should probably build |
| your pata_parport drivers as modules, and arrange to do the printer reset |
| before loading the pata_parport drivers. |
