On Tue, 2011-03-22 at 23:04 +0900, Paul Mundt wrote: > On Sat, Mar 19, 2011 at 01:47:27AM +0100, Rafael J. Wysocki wrote: > > On Thursday, March 17, 2011, Paul Mundt wrote: > > > On Sun, Mar 13, 2011 at 02:03:49PM +0100, R. J. Wysocki wrote: > > > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > > > Convert the SuperH clocks framework and shared interrupt handling > > > > code to using struct syscore_ops instead of a sysdev classes and > > > > sysdevs for power managment. > > > > > > > > This reduces the code size significantly and simplifies it. The > > > > optimizations causing things not to be restored after creating a > > > > hibernation image are removed, but they might lead to undesirable > > > > effects during resume from hibernation (e.g. the clocks would be left > > > > as the boot kernel set them, which might be not the same way as the > > > > hibernated kernel had seen them before the hibernation). > > > > > > > > This also is necessary for removing sysdevs from the kernel entirely > > > > in the future. > > > > > > > > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> > > > > > > This misses the use of the sysdev class by the userimask code, though I'm > > > open to suggestions for alternatives. > > > > For now, I'd simply move the sysdev class definition to userimask.c, like > > in the patch below. The current goal is to eliminate the suspend/resume and > > shutdown operations from sysdevs (and sysdev drivers), the next step will > > be to replace the remaining sysdevs with alternative mechanisms. > > > It's not quite that straightforward, you've also killed off the name > attribute for each of the intc sysdevs, so we no longer have a visible > way to map a given intc controller number to the controller name in a > user visible way. > > I'm not opposed to the syscore thing for suspend/resume ops, but I'm not > willing to trash the userimask and name mapping interface in the process > with no alternatives. > > userimask was the first global configuration item I added, but there are > other per-controller and global configuration knobs that I plan to export > through the interface, so there really needs to be a compelling reason > for moving off of sysdevs. Yes, they don't fit into the model. They have been a dumb hack from the first day, and never integrated into the kenrel driver core or hotplug properly. If you need the userspace visibility, better just add a "struct bus_type" with a proper name for your subsystem and register a "struct device" with the bus_type assigned for all of them, instead of using the broken concept of sydevs. You can even make them show up in /sys/devices/system/<bus_type name>/<struct device name>/ if you want to. That way userspace can properly enumerate them in a flat list in /sys/bus/<bus_type name>/devices/*, and gets proper events on module load and during system coldplug, and can hook into the usual hotplug pathes to set/get these values instead of crawling magicly defined and decoupled locations in /sys which can not express proper hierarchy, classicication, or anything else that all other devices can just do. There is really no reason for any device being a magic and conceptually broken sysdev today - just to be different from any other device the kernel exports to userspace. Thanks, Kay _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
