Add a flag to disable FIFO probing. The code seems to have a chance of

misdetecting FIFO capabilities, at least on my girlfriend's Thinkpad 755,
the driver doesn't work using the FIFO.

While i was at it, i (partially) fixed option FCC_YE since it would no
longer have compiled at all under -current.  I've also made an attempt
to document the device driver flags value (ab-)used internally by this
option.

RELENG_3 candidate, but with a slightly different patch there (will go
to jkh in email).

1 files changed, 14 insertions, 0 deletions

diff --git a/share/man/man4/fdc.4 b/share/man/man4/fdc.4
index 97348c1..f837eb0 100644
--- a/share/man/man4/fdc.4
+++ b/share/man/man4/fdc.4
@@ -53,6 +53,20 @@ configuration value in their CMOS.  Use the flags value
 .Ql 0x1
 to pretend a 1.44 MB floppy drive as the first unit, without asking the
 CMOS for it.
+.Pp
+The flags value
+.Ql 0x2
+is reserved for PCMCIA floppy use, and should never be set in a
+configuration file directly.  It is internally handled in the driver
+if the compilation option
+.Dv FDC_YE
+is set, and defers device probing.
+.Pp
+Normally, the device driver detects FDC chipsets that have an internal
+FIFO, and enables the FIFO on them.  There is a slight chance that this
+feature is actually misdetected (seen on an IBM Thinkpad 755c), so it
+can be turned off using flags
+.Ql 0x4 .
 .Sh FILES
 .Bl -tag -width Pa -compact
 .It /dev/fd*