GNU Info
(fdutils.info)Boottime configuration
Configuring the floppy driver via lilo or insmod
************************************************
The floppy driver is configured using the `floppy=' options in lilo.
These options can be typed at the boot prompt, or entered in the lilo
configuration file.
Example: If your kernel is called `linux-2.0', type the following
line at the lilo boot prompt (if you have a thinkpad):
linux-2.0 floppy=thinkpad
You may also enter the following line in `/etc/lilo.conf', in the
description of `linux-2.0':
append = "floppy=thinkpad"
Several floppy related options may be given, example:
linux-2.0 floppy=daring floppy=two_fdc
append = "floppy=daring floppy=two_fdc"
If you give options both in the lilo config file and on the boot
prompt, the option strings of both places are concatenated, the boot
prompt options coming last. That's why there are also options to
restore the default behaviour.
If you use the floppy driver as a module, use the following syntax:
`insmod floppy 'floppy="OPTIONS"''. (This line may be unreadable in the
info version of this document. If so, please refer to the printed
version).
Example:
insmod floppy 'floppy="daring two_fdc"'
Note that in this case `floppy=' should only be typed out once, and
not once for each option. You need at least modules-1.3.57 for this
method. However, the older environment variable based syntax is still
available:
Bourne (sh, bash, ksh, zsh) syntax:
`floppy="daring two_fdc" insmod floppy'
C-shell (csh, tcsh) syntax:
`setenv floppy "daring two_fdc" ; insmod floppy'
Some versions of insmod are buggy in one way or another. If you have
any problems (options not being passed correctly, segfaults during
insmod), first check whether there is a more recent version. If there
isn't, use the old method using environment variables. Problems with
`insmod' happen mostly for options involving both a number and a
string, such as `floppy=0,4,cmos'. Options only involving strings,
such as `floppy=daring' are not affected.
The floppy related options include:
`floppy=daring'
Tells the floppy driver that you have a well behaved floppy
controller. This allows more efficient and smoother operation,
but may fail on certain controllers.
`floppy=0,daring'
Tells the floppy driver that your floppy controller should be used
with caution.
`floppy=one_fdc'
Tells the floppy driver that you have only floppy controller
(default)
`floppy=two_fdc'
`floppy=ADDRESS,two_fdc'
Tells the floppy driver that you have two floppy controllers. The
second floppy controller is assumed to be at ADDRESS. If ADDRESS is
not given, 0x370 is assumed. two_fdc is implied if you use the cmos
option with a drive of id 4 to 7.
`floppy=thinkpad'
Tells the floppy driver that you have a Thinkpad. Thinkpads use an
inverted convention for the disk change line.
`floppy=0,thinkpad'
Tells the floppy driver that you don't have a Thinkpad.
`floppy=omnibook'
`floppy=nodma'
Tells the floppy driver not to use Dma for data transfers. This is
needed for instance on some HP Omnibooks, which don't have a
workable DMA channel for the floppy driver. This option is also
useful if you frequently get "Unable to allocate DMA memory"
messages. Indeed, dma memory needs to be continuous in physical
memory, and is thus harder to find, whereas non-dma buffers may be
allocated in virtual memory. However, I advise against this if
you have an FDC without a FIFO (8272A or 82072). 82072A and later
are OK. You also need at least a 486 to use nodma. If you use
nodma mode, I suggest you also set the FIFO threshold to 10 or
lower, in order to limit the number of data transfer interrupts.
`floppy=dma'
Tells the floppy driver that a workable DMA channel is available
(the default).
`floppy=nofifo'
Disables the FIFO entirely. This is needed if you get "Bus master
arbitration error" messages from your ethernet card (or from other
devices) while accessing the floppy.
`floppy=fifo'
Enables the FIFO (default)
`floppy=THRESHOLD,fifo_depth'
Sets the FIFO threshold. This is mostly relevant in DMA mode. If
this is higher, the floppy driver tolerates more interrupt
latency, but it triggers more interrupts (i.e. it imposes more
load on the rest of the system). If this is lower, the interrupt
latency should be lower too (faster processor). The benefit of a
lower threshold is less interrupts.
To tune the fifo threshold, switch on over/underrun messages using
`floppycontrol --messages'. Then access a floppy disk. If you get a
huge amount of `Over/Underrun - retrying' messages, then the fifo
threshold is too low. Try with a higher value, until you only get
an occasional Over/Underrun. It is a good idea to compile the
floppy driver as a module when doing this tuning. Indeed, it
allows to try different fifo values without rebooting the machine
for each test. Note that you need to do `floppycontrol --messages'
every time you re-insert the module.
Usually, tuning the fifo threshold should not be needed, as the
default (0xa) is reasonable.
`floppy=DRIVE,TYPE,cmos'
Sets the cmos type of DRIVE to TYPE. Additionnaly, this drive is
allowed in the bitmask. This is useful if you have more than two
floppy drives (only two can be described in the physical cmos), or
if your BIOS uses non-standard CMOS types. The CMOS types are:
`0'
unknown or not installed
`1'
5 1/4 DD
`2'
5 1/4 HD
`3'
3 1/2 DD
`4'
3 1/2 HD
`5'
3 1/2 ED
`6'
3 1/2 ED
Note that there are two valid types for ED drives. This is because
5 was initially chosen to represent floppy tapes, and 6 for ED
drives. AMI ignored this, and used 5 for ED drives. That's why
the floppy driver handles both) Setting the CMOS to 0 for the
first two drives (default) makes the floppy driver read the
physical cmos for those drives.
`floppy=unexpected_interrupts'
Print a warning message when an unexpected interrupt is received
(default behaviour)
`floppy=no_unexpected_interrupts'
`floppy=L40SX'
Don't print a message when an unexpected interrupt is received.
This is needed on IBM L40SX laptops in certain video modes. (There
seems to be an interaction between video and floppy. The
unexpected interrupts only affect performance, and can safely be
ignored.)
`floppy=broken_dcl'
Don't use the disk change line, but assume that the disk was
changed whenever the device node is reopened. Needed on some boxes
where the disk change line is broken or unsupported. This should
be regarded as a stopgap measure, indeed it makes floppy operation
less efficient due to unneeded cache flushings, and slightly more
unreliable. Please verify your cable, connection and jumper
settings if you have any DCL problems. However, some older
drives, and also some Laptops are known not to have a DCL.
`floppy=debug'
Print debugging messages
`floppy=messages'
Print informational messages for some operations (disk change
notifications, warnings about over and underruns, and about
autodetection)
`floppy=silent_dcl_clear'
Uses a less noisy way to clear the disk change line (which doesn't
involve seeks). Implied by daring.
(There are other options as well, but they are considered
obsolete, and thus they are not documented here)
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