d/freebsd-skq
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

When loading a driver that is a subclass of another driver don't set the

Browse Source 
devclass's parent pointer if the two drivers share the same devclass.  This
can happen if the drivers use the same new-bus name.  For example, we
currently have 3 drivers that use the name "pci": the generic PCI bus
driver, the ACPI PCI bus driver, and the OpenFirmware PCI bus driver.  If
the ACPI PCI bus driver was defined as a subclass of the generic PCI bus
driver, then without this check the "pci" devclass would point to itself
as its parent and device_probe_child() would spin forever when it
encountered the first PCI device that did have a matching driver.

Reviewed by:	dfr, imp, new-bus@
This commit is contained in:
John Baldwin 2006-01-20 21:59:13 +00:00
parent fe2f3fab4a
commit 267ec43593
1 changed files with 11 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
sys/kern/subr_bus.c
View File

@ -781,7 +781,17 @@ devclass_find_internal(const char *classname, const char *parentname,
bus_data_generation_update();
}
if (parentname && dc && !dc->parent) {
/*
* If a parent class is specified, then set that as our parent so
* that this devclass will support drivers for the parent class as
* well. If the parent class has the same name don't do this though
* as it creates a cycle that can trigger an infinite loop in
* device_probe_child() if a device exists for which there is no
* suitable driver.
*/
if (parentname && dc && !dc->parent &&
strcmp(classname, parentname) != 0) {
dc->parent = devclass_find_internal(parentname, 0, FALSE);
}