Hello, Rafael. On Tue, Dec 17, 2013 at 03:34:00AM +0100, Rafael J. Wysocki wrote: > No, it isn't. [I guess it was originally, but it has not been the case > for a very long time.] It is about getting user space interactions (all of
Heh... no wonder people are all so confused about this thing. > the sysfs/ioctl/mmap/read/write/you-name-it thingies user space can do to > devices) when we're calling device suspend/resume routines. The reason is > that otherwise all of them would have had to do a "oh, are we suspending by > the way?" check pretty much on every code path that can be triggered by > user space. Freezing userland is fine. I have no problem with that but up until now the only use case that seems fundamentally valid to me is freezing IO processing kthread in a driver as a cheap way to implement suspend/resume. At this point, given the general level of confusion, it seems to be costing more than benefiting. > > Does that mean that it's safe to unfreeze before invoking resume? > > No, it isn't. So, are you saying it's really about giving device drivers easy way to implement suspend/resume? If that's the case, let's please make it *way* more specific and clear - ie. things like helpers to implement suspend/resume hooks trivially or whatnot. Freezable kthreads (and now workqueues) have been becoming a giant mess for a while now. Thanks. -- tejun -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
