On Wednesday 06 December 2006 3:56 pm, Marco d'Itri wrote: > On Dec 06, David Brownell <[EMAIL PROTECTED]> wrote: > > > > Please explain in more details how hotplugging would be broken, possibly > > > with examples. > > > > First, for reference, I refer to hotplugging using the trivial ASH scripts > > from [1], updated by removing no-longer-needed special cases for > > platform_bus > > (that original logic didn't work sometimes) and pcmcia. See the (short) > > I.e. a quick hack which has never been used by any distribution.
Not a "quick hack" at all; boiling down hotplug + coldplug to something that tight got a fair degree of thought back then. It takes work to get things to be small enough to use on very small Linux-based systems. As for "never been used" ... you can't know that, given that embedded distros are normally custom built. I'm certain that I submitted it to buildroot back then. So a lot of folk building custom distros have had access to that, and I'd be surprised if it was "never" used. > And anyway some kernel component is supposed to provide the aliases > pointing from the $MODALIAS values to the drivers, so modprobe $MODALIAS > would still work. A driver named "foo" is usually named "foo.ko"; aliases not needed, or even desirable. The kernel source tree has done that for years. > > Second, note that you're asking me to construct a straw man for you and > > then break it down, since nobody arguing with the $SUBJECT patch has ever > > provided a complete counter-proposal (much less respond to the points > > I've made about legacy driver bugginess -- which is suggestive). > > I am asking what is the point for a module to provide its own name in > $MODALIAS. As I pointed out previously, more than once: it's providing a driver identifier there, all it needs is to be understood by "modprobe". > $MODALIAS is available only *after* the module has been loaded by > something else. You seem like you're being intentionally dense here ... that's rarely true, which is what makes hotplug-driven driver loading work. The $MODALIAS thing is passed to userspace after creation of driver model device nodes. (Contrary to what you said above. It's related to add_device calls, not module loading.) Normal driver modules do not create those nodes ... and $MODALIAS is used as a driver identifier so that /sbin/hotplug can "modprobe $MODALIAS" to load the right driver module. But *legacy* driver modules are not well behaved; they create those nodes themselves, rather than letting bus infrastructure do so. Which is why they are not hotpluggable. The $SUBJECT patch just turns off $MODALIAS based hotplugging for those ill-mannered drivers. - Dave - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
