diff options
| -rw-r--r-- | share/man/man4/io.4 | 22 |
1 files changed, 13 insertions, 9 deletions
diff --git a/share/man/man4/io.4 b/share/man/man4/io.4 index 31766da..7ceacae 100644 --- a/share/man/man4/io.4 +++ b/share/man/man4/io.4 @@ -72,22 +72,25 @@ all of them. The .Dv IODEV_PIO is used by all the architectures in order to request that an I/O operation -be performed. It takes a 'struct iodev_pio_req' argument -that must be previously setup. +be performed. +It takes a 'struct iodev_pio_req' argument that must be previously setup. .Pp The .Fa access -member specifies the type of operation requested. It may be: +member specifies the type of operation requested. +It may be: .Bl -tag -width IODEV_PIO_WRITE .It Dv IODEV_PIO_READ -The operation is an "in" type. A value will be read from the specified port +The operation is an "in" type. +A value will be read from the specified port (retrieved from the .Fa port member) and the result will be stored in the .Fa val member. .It Dv IODEV_PIO_WRITE -The operation is a "out" type. The value will be fetched from the +The operation is a "out" type. +The value will be fetched from the .Fa val member and will be written out to the specified port (defined as the .Fa port @@ -105,13 +108,14 @@ the kernel enforces that only the super-user may open this device. .Sh LEGACY The .Pa /dev/io -interface used to be very i386 specific and worked differently. The initial -implementation, in fact, simply raised the +interface used to be very i386 specific and worked differently. +The initial implementation simply raised the .Em IOPL of the current thread when .Xr open 2 -was called on the file. This behaviour is retained in the current -implementation as legacy support for both i386 and amd64 architectures. +was called on the device. +This behaviour is retained in the current implementation as legacy +support for both i386 and amd64 architectures. .Sh SEE ALSO .Xr close 2 , .Xr i386_get_ioperm 2 , |
