Hi, On Tue, Feb 26, 2013 at 12:39:50AM +0100, Rafael J. Wysocki wrote: > On Monday, February 25, 2013 11:07:52 AM Toshi Kani wrote: > > On Sat, 2013-02-23 at 22:38 +0000, Rafael J. Wysocki wrote: > > > From: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > > > > > > Multiple drivers handling hotplug-capable ACPI device nodes install > > > notify handlers covering the same types of events in a very similar > > > way. Moreover, those handlers are installed in separate namespace > > > walks, although that really should be done during namespace scans > > > carried out by acpi_bus_scan(). This leads to substantial code > > > duplication, unnecessary overhead and behavior that is hard to > > > follow. > > > > > > For this reason, introduce common code in drivers/acpi/scan.c for > > > handling hotplug-related notification and carrying out device > > > insertion and eject operations in a generic fashion, such that it > > > may be used by all of the relevant drivers in the future. To cover > > > the existing differences between those drivers introduce struct > > > acpi_hotplug_profile for representing collections of hotplug > > > settings associated with different ACPI scan handlers that can be > > > used by the drivers to make the common code reflect their current > > > behavior. [...] > That's correct, but I don't know what the user space expectations are > currently. > > > So, I'd suggest the following changes. > > - Remove the "uevents" attribute. KOBJ_ONLINE/OFFLINE are not used for > > ACPI device objects. > > - Make the !autoeject case as an exception for now, and emit > > KOBJ_OFFLINE as a way to request off-lining to user. This uevent is > > tied with the !autoeject case. We can then revisit if this use-case > > needs to be supported going forward. If so, we may want to consider a > > different event type. > > Well, what about avoiding to expose uevents and autoeject for now and > exposing enabled only? Drivers would still be able to set the other flags on > init on init to enforce the backwards-compatible behavior. Now that we don't define uevents and autoeject in v2 of this series, could you explain how we get safe ejection from userspace e.g. for memory hot-remove? What are the other flags drivers can use (on init?) to avoid autoeject and only issue KOBJ_OFFLINE? > > I agree that it would be sufficient to use one additional flag then, to start > with, but its meaning would be something like "keep backwards compatibility > with the old container driver", so perhaps "autoeject" is not a good name. > > What about "user_eject" (that won't be exposed to user space) instead? Where, > if set, it would meand "do not autoeject and emit KOBJ_OFFLINE/ONLINE uevents > like the old container driver did"? I don't see user_eject in v2. Is it unnecessary for userspace ejection control or planned for later? Also why shouldn't it be exposed to userpace? thanks, - Vasilis -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
