From f52c5866ead1319d260be5c1a95cf8ef009bea0b Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Sun, 29 Aug 2004 18:25:21 +0000 Subject: Initial support (disabled) for rebidding devices. I've been running this in my tree for a while and in its disabled state there are no issues. It isn't enabled yet because some drivers (in acpi) have side effects in their probe routines that need to be resolved in some manner before this can be turned on. The consensus at the last developer's summit was to provide a static method for each driver class that will return characteristics of the driver, one of which is if can be reprobed idempotently. --- sys/kern/subr_bus.c | 40 ++++++++++++++++++++++++++++++++++++---- 1 file changed, 36 insertions(+), 4 deletions(-) diff --git a/sys/kern/subr_bus.c b/sys/kern/subr_bus.c index 9b1cafc18fe73..18f4362fd9336 100644 --- a/sys/kern/subr_bus.c +++ b/sys/kern/subr_bus.c @@ -124,6 +124,7 @@ struct device { #define DF_QUIET 16 /* don't print verbose attach message */ #define DF_DONENOMATCH 32 /* don't execute DEVICE_NOMATCH again */ #define DF_EXTERNALSOFTC 64 /* softc not allocated by us */ +#define DF_REBID 128 /* Can rebid after attach */ u_char order; /**< order from device_add_child_ordered() */ u_char pad; void *ivars; /**< instance variables */ @@ -1562,7 +1563,11 @@ device_probe_child(device_t dev, device_t child) if (!dc) panic("device_probe_child: parent device has no devclass"); - if (child->state == DS_ALIVE) + /* + * If the state is already probed, then return. However, don't + * return if we can rebid this object. + */ + if (child->state == DS_ALIVE && (child->flags & DF_REBID) == 0) return (0); for (; dc; dc = dc->parent) { @@ -1618,7 +1623,28 @@ device_probe_child(device_t dev, device_t child) /* * If we found a driver, change state and initialise the devclass. */ + /* XXX What happens if we rebid and got no best? */ if (best) { + /* + * If this device was atached, and we were asked to + * rescan, and it is a different driver, then we have + * to detach the old driver and reattach this new one. + * Note, we don't have to check for DF_REBID here + * because if the state is > DS_ALIVE, we know it must + * be. + * + * This assumes that all DF_REBID drivers can have + * their probe routine called at any time and that + * they are idempotent as well as completely benign in + * normal operations. + * + * We also have to make sure that the detach + * succeeded, otherwise we fail the operation (or + * maybe it should just fail silently? I'm torn). + */ + if (child->state > DS_ALIVE && best->driver != child->driver) + if ((result = device_detach(dev)) != 0) + return (result); if (!child->devclass) device_set_devclass(child, best->driver->name); device_set_driver(child, best->driver); @@ -1628,7 +1654,11 @@ device_probe_child(device_t dev, device_t child) * sure that we have the right description. */ DEVICE_PROBE(child); - } +#if 0 + child->flags |= DF_REBID; +#endif + } else + child->flags &= ~DF_REBID; child->state = DS_ALIVE; bus_data_generation_update(); @@ -2140,7 +2170,7 @@ device_probe_and_attach(device_t dev) { int error; - if (dev->state >= DS_ALIVE) + if (dev->state >= DS_ALIVE && (dev->flags & DF_REBID) == 0) return (0); if (!(dev->flags & DF_ENABLED)) { @@ -2839,7 +2869,8 @@ bus_generic_driver_added(device_t dev, driver_t *driver) DEVICE_IDENTIFY(driver, dev); TAILQ_FOREACH(child, &dev->children, link) { - if (child->state == DS_NOTPRESENT) + if (child->state == DS_NOTPRESENT || + (child->flags & DF_REBID)) device_probe_and_attach(child); } } @@ -3529,6 +3560,7 @@ print_device_short(device_t dev, int indent) (dev->flags&DF_FIXEDCLASS? "fixed,":""), (dev->flags&DF_WILDCARD? "wildcard,":""), (dev->flags&DF_DESCMALLOCED? "descmalloced,":""), + (dev->flags&DF_REBID? "rebiddable,":""), (dev->ivars? "":"no "), (dev->softc? "":"no "), dev->busy)); -- cgit v1.3