| devctl.4 (110718) | devctl.4 (111447) |
|---|---|
| 1.\" 2.\" Copyright (c) 2002 M. Warner Losh 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" | 1.\" 2.\" Copyright (c) 2002 M. Warner Losh 3.\" All rights reserved. 4.\" 5.\" Redistribution and use in source and binary forms, with or without 6.\" modification, are permitted provided that the following conditions 7.\" are met: 8.\" 1. Redistributions of source code must retain the above copyright --- 8 unchanged lines hidden (view full) --- 17.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 18.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 19.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 20.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 21.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 22.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 23.\" SUCH DAMAGE. 24.\" |
| 25.\" $FreeBSD: head/share/man/man4/devctl.4 110718 2003-02-11 17:36:38Z imp $ | 25.\" $FreeBSD: head/share/man/man4/devctl.4 111447 2003-02-24 22:53:26Z ru $ |
| 26.\" 27.Dd February 11, 2003 28.Dt DEVCTL 4 29.Os 30.Sh NAME 31.Nm devctl | 26.\" 27.Dd February 11, 2003 28.Dt DEVCTL 4 29.Os 30.Sh NAME 31.Nm devctl |
| 32.Nd Device event reporting and device control interface. | 32.Nd "device event reporting and device control interface" |
| 33.Sh DESCRIPTION 34The 35.Nm 36device is used to report device events from the kernel. 37Future versions will allow for some device control as well. 38.Sh IMPLEMENTATION NOTES | 33.Sh DESCRIPTION 34The 35.Nm 36device is used to report device events from the kernel. 37Future versions will allow for some device control as well. 38.Sh IMPLEMENTATION NOTES |
| 39This design allows only one reader for /dev/devctl. | 39This design allows only one reader for 40.Pa /dev/devctl . |
| 40This is not desirable 41in the long run, but will get a lot of hair out of this implementation. 42Maybe we should make this device a clonable device. 43.Pp | 41This is not desirable 42in the long run, but will get a lot of hair out of this implementation. 43Maybe we should make this device a clonable device. 44.Pp |
| 44Also note: we specifically do not attach a device to the device_t tree | 45Also note: we specifically do not attach a device to the 46.Vt device_t 47tree |
| 45to avoid potential chicken and egg problems. 46One could argue that all of this belongs to the root node. | 48to avoid potential chicken and egg problems. 49One could argue that all of this belongs to the root node. |
| 47One could also further argue that the sysctl interface that we have 48not might more properly be an ioctl interface. | 50One could also further argue that the 51.Xr sysctl 3 52interface that we have now might more properly be an 53.Xr ioctl 2 54interface. |
| 49.Pp | 55.Pp |
| 50SIGIO support is included in the driver. 51However, the author is not sure that the SIGIO support is done correctly. 52It was copied from a driver that had SIGIO support that likely hasn't been 53tested since 3.4 or 2.2.8! | 56.Dv SIGIO 57support is included in the driver. 58However, the author is not sure that the 59.Dv SIGIO 60support is done correctly. 61It was copied from a driver that had 62.Dv SIGIO 63support that likely has not been 64tested since 65.Fx 3.4 66or 67.Fx 2.2.8 ! |
| 54.Pp 55The read channel for this device is used to report changes to 56userland in realtime. 57We return one record at a time. 58If you try to read this device a character at a time, you will loose 59the rest of the data. 60Listening programs are expected to cope. 61.Pp | 68.Pp 69The read channel for this device is used to report changes to 70userland in realtime. 71We return one record at a time. 72If you try to read this device a character at a time, you will loose 73the rest of the data. 74Listening programs are expected to cope. 75.Pp |
| 62The sysctl and boot parameter hw.bus.devctl_disable is used to disable | 76The sysctl and boot parameter 77.Va hw.bus.devctl_disable 78is used to disable |
| 63.Nm | 79.Nm |
| 64when no devd is running. | 80when no 81.Xr devd 8 82is running. |
| 65.Sh PROTOCOL | 83.Sh PROTOCOL |
| 84The |
|
| 66.Nm | 85.Nm |
| 67uses an ASCII protocol. | 86device 87uses an 88.Tn ASCII 89protocol. |
| 68The driver returns one record at a time to its readers. 69Each record is terminated with a newline. 70The first character of the record is the event type. 71.Pp 72.Bl -column -compact "Type" "Description" 73.Em "Type Description" | 90The driver returns one record at a time to its readers. 91Each record is terminated with a newline. 92The first character of the record is the event type. 93.Pp 94.Bl -column -compact "Type" "Description" 95.Em "Type Description" |
| 74+ Device node in tree attached 75- Device node in tree detached 76? Unknown device detected | 96+ Device node in tree attached. 97- Device node in tree detached. 98? Unknown device detected. |
| 77.El | 99.El |
| 78.Ss Message formats | 100.Ss Message Formats |
| 79Except for the first character in the record, attach and detach 80messages have the same format. | 101Except for the first character in the record, attach and detach 102messages have the same format. |
| 81.D1 Tdev at parent on location 82.Bl -column -compact "Part" "Description" | 103.Pp 104.D1 Ar T Ns Ar dev Li at Ar parent Li on Ar location 105.Pp 106.Bl -column -compact "location" "Description" |
| 83.Em "Part Description" | 107.Em "Part Description" |
| 84T + or - 85dev The device name that was attached/detached 86parent The device name of the parent bus that attached the device 87location Bus specific location information | 108.It Ar T Ta "+ or -" 109.It Ar dev Ta "The device name that was attached/detached." 110.It Ar parent Ta "The device name of the parent bus that attached the device." 111.It Ar location Ta "Bus specific location information." |
| 88.El 89.Pp 90The nomatch messages can be used to load devices driver. 91If you load a device driver, then one of two things can happen. | 112.El 113.Pp 114The nomatch messages can be used to load devices driver. 115If you load a device driver, then one of two things can happen. |
| 92If the device driver attaches to something, you'll get a device | 116If the device driver attaches to something, you will get a device |
| 93attached message. | 117attached message. |
| 94If it doesn't, then nothing will happen. | 118If it does not, then nothing will happen. |
| 95.Pp 96The attach and detach messages arrive after the event. 97This means one cannot use the attach message to load an alternate 98driver. 99The attach message driver has already claimed this device. 100One cannot use the detach messages to flush data to the device. 101The device is already gone. 102.Sh SEE ALSO 103.Xr devd 8 | 119.Pp 120The attach and detach messages arrive after the event. 121This means one cannot use the attach message to load an alternate 122driver. 123The attach message driver has already claimed this device. 124One cannot use the detach messages to flush data to the device. 125The device is already gone. 126.Sh SEE ALSO 127.Xr devd 8 |
| 104 | |