.Sh SYSCTL VARIABLES

.Bl -tag -width "debug.fdc.debugflags"

.It Dv debug.fdc.debugflags

Selectively enable debugging by setting one or more flags.

.Bl -tag -width "0x40"

.It Dv 0x01

Dump device registers on reset.

.It Dv 0x02

When an IO operation completes, print the number of retries

when that number is greater than zero.

.It Dv 0x04

Print when the number of retries exceeds

.Dv debug.fdc.retries

.Pq Dv EIO .

Print when the option

.Dv FDOPT_NOERROR

is set and an error would have returned from a write operation.

.It Dv 0x08

Print detailed IO command information.

.It Dv 0x10

Print status registers.

.It Dv 0x20

Print detailed status registers when interrupts complete.

Print the source code line number close to the source of a

non-zero return from a thread worker operation.

.It Dv 0x40

Print when the disk appears to be lost.

Print cylinder, head, sector, and sector shift information

after a request to read an ID field.

Notify whether a disk probe resulted in finding a disk.

When detecting the density of media present, indicate whether

the autosensing was successful, and if so, the size of the

medium in kilobytes.

Print detailed type information when setting the drive type.

.It Dv 0x80

Print when an unknown IOCTL is used.

.El

.It Dv debug.fdc.fifo

For enhanced controllers, allows a non-default FIFO

threshold setting. The default is 8 bytes.

.It Dv debug.fdc.retries

Maximum number of retries to attempt. The default is 10.

.It Dv debug.fdc.spec1

Specification byte one (step-rate + head unload).

The default step rate is 6 ms. The default head unload

time is 240 ms.

.It Dv debug.fdc.spec2

Specification byte two (head load time + no-dma).

The default head load time is 16 ms, and no-dma is 0

.Pq disabled .

.It Dv debug.fdc.settle

Head settling time in

.Sy settle

/ hz seconds. The default value is set during device attach.

.El