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author | imp <imp@FreeBSD.org> | 2004-04-11 06:37:21 +0000 |
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committer | imp <imp@FreeBSD.org> | 2004-04-11 06:37:21 +0000 |
commit | c52b25a0e51c7b7745e4c53060d44e08a9642b76 (patch) | |
tree | 64d4773607453fffb0d12cfae565d27e481d642c /share/man/man9/DEVICE_PROBE.9 | |
parent | 0f6d9cd13e406c8f6a0d8a3b06e847147886d6e9 (diff) | |
download | FreeBSD-src-c52b25a0e51c7b7745e4c53060d44e08a9642b76.zip FreeBSD-src-c52b25a0e51c7b7745e4c53060d44e08a9642b76.tar.gz |
Document more clearly that a probe routine:
Should have no side effects
Must not hold resources when it returns
May be called multiple times if it returns < 0.
Remove the bad advise that the probe routine should look for children
for devices that implement busses. This is more properly reserved for
the attach routine.
Diffstat (limited to 'share/man/man9/DEVICE_PROBE.9')
-rw-r--r-- | share/man/man9/DEVICE_PROBE.9 | 16 |
1 files changed, 8 insertions, 8 deletions
diff --git a/share/man/man9/DEVICE_PROBE.9 b/share/man/man9/DEVICE_PROBE.9 index daac502..5c4b00f 100644 --- a/share/man/man9/DEVICE_PROBE.9 +++ b/share/man/man9/DEVICE_PROBE.9 @@ -64,15 +64,14 @@ In particular, it must not assume that any values stored in the softc structure will be available for its attach method and any resources allocated during probe must be released and re-allocated if the attach method is called. -If a success code of zero is -returned, the driver can assume that it will be the one attached. +In addition it is an absolute requirement that the probe routine have +no side effects whatsoever. +The probe routine may be called more than once before the attach +routine is called. .Pp -Devices which implement busses should use this method to probe for -the existence of devices attached to the bus and add them as -children. -If this is combined with the use of -.Xr bus_generic_attach 9 -the child devices will be automatically probed and attached. +If a success code of zero is +returned, the driver can assume that it will be the one attached, but +must not hold any resources when the probe routine returns. .Sh RETURN VALUES A value equal to or less than zero indicates success, greater than zero indicates an error (errno). For values equal to or less than @@ -81,6 +80,7 @@ for a value less than zero, the lower the value the lower the priority, e.g. -100 indicates a lower priority than -50. .Sh SEE ALSO .Xr device 9 , +.Xr DEVICE_ATTACH 9 , .Xr DEVICE_DETACH 9 , .Xr DEVICE_IDENTIFY 9 , .Xr DEVICE_SHUTDOWN 9 |