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              README FOR LINUX SONY CDU-535/531 DRIVER

              ========================================

This is the Sony CDU-535 (and 531) driver version 0.7 for Linux.

I do not think I have the documentation to add features like DMA support

so if anyone else wants to pursue it or help me with it, please do.

(I need to see what was done for the CDU-31A driver -- perhaps I can

steal some of that code.)

This is a Linux device driver for the Sony CDU-535 CDROM drive.  This is

one of the older Sony drives with its own interface card (Sony bus).

The DOS driver for this drive is named SONY_CDU.SYS - when you boot DOS

your drive should be identified as a SONY CDU-535.  The driver works

with a CDU-531 also.  One user reported that the driver worked on drives

OEM'ed by Procomm, drive and interface board were labelled Procomm.

The Linux driver is based on Corey Minyard's sonycd 0.3 driver for

the CDU-31A.  Ron Jeppesen just changed the commands that were sent

to the drive to correspond to the CDU-535 commands and registers.

There were enough changes to let bugs creep in but it seems to be stable.

Ron was able to tar an entire CDROM (should read all blocks) and built

ghostview and xfig off Walnut Creek's X11R5/GNU CDROM.  xcdplayer and

workman work with the driver.  Others have used the driver without

problems except those dealing with wait loops (fixed in third release).

Like Minyard's original driver this one uses a polled interface (this

is also the default setup for the DOS driver).  It has not been tried

with interrupts or DMA enabled on the board.

REQUIREMENTS

============

        - Sony CDU-535 drive, preferably without interrupts and DMA

          enabled on the card.

        - Drive must be set up as unit 1.  Only the first unit will be

          recognized

        - you must enter your interface address into

          /usr/src/linux/include/linux/sonycd535.h and build the

          appropriate kernel or use the "kernel command line" parameter

                sonycd535=0x320

          with the correct interface address.

NOTES:

======

1) The drive MUST be turned on when booting or it will not be recognized!

   (but see comments on modularized version below)

2) when the cdrom device is opened the eject button is disabled to keep the

   user from ejecting a mounted disk and replacing it with another.

   Unfortunately xcdplayer and workman also open the cdrom device so you

   have to use the eject button in the software.  Keep this in mind if your

   cdrom player refuses to give up its disk -- exit workman or xcdplayer, or

   umount the drive if it has been mounted.

THANKS

======

Many thanks to Ron Jeppesen (ronj.an@site007.saic.com) for getting

this project off the ground.  He wrote the initial release

and the first two patches to this driver (0.1, 0.2, and 0.3).

Thanks also to Eberhard Moenkeberg (emoenke@gwdg.de) for prodding

me to place this code into the mainstream Linux source tree

(as of Linux version 1.1.91), as well as some patches to make

it a better device citizen.  Further thanks to "S. Joel Katz"

 for his MODULE patches (see details below),

Porfiri Claudio  for patches

to make the driver work with the older CDU-510/515 series, and

Heiko Eissfeldt  for pointing out that

the verify_area() checks were ignoring the results of said checks.

(Acknowledgments from Ron Jeppesen in the 0.3 release:)

Thanks to Corey Minyard who wrote the original CDU-31A driver on which

this driver is based.  Thanks to Ken Pizzini and Bob Blair who provided

patches and feedback on the first release of this driver.

Ken Pizzini

ken@halcyon.com

------------------------------------------------------------------------------

(The following is from Joel Katz .)

        To build a version of sony535.o that can be installed as a module,

use the following command:

gcc -c -D__KERNEL__ -DMODULE -O2 sonycd535.c -o sonycd535.o

        To install the module, simply type:

insmod sony535.o

        or

insmod sony535.o sonycd535=

        And to remove it:

rmmod sony535

        The code checks to see if MODULE is defined and behaves as it used

to if MODULE is not defined. That means your patched file should behave

exactly as it used to if compiled into the kernel.

        I have an external drive, and I usually leave it powered off. I used

to have to reboot if I needed to use the CDROM drive. Now I don't.

        Even if you have an internal drive, why waste the 268K of memory

(unswappable) that the driver uses if you use your CD-ROM drive infrequently?

        This driver will not install (whether compiled in or loaded as a

module) if the CDROM drive is not available during its initialization. This

means that you can have the driver compiled into the kernel and still load

the module later (assuming the driver doesn't install itself during

power-on). This only wastes 12K when you boot with the CDROM drive off.

        This is what I usually do; I leave the driver compiled into the

kernel, but load it as a module if I powered the system up with the drive

off and then later decided to use the CDROM drive.

        Since the driver only uses a single page to point to the chunks,

attempting to set the buffer cache to more than 2 Megabytes would be very

bad; don't do that.