Vipin K Parashar <vi...@linux.vnet.ibm.com> writes: > (1) Environmental and Power Warning (EPOW) > (2) Delayed Power Off (DPO) > The user interface for this driver is /dev/opal_event character > device file where the user space clients can poll and read for > new opal platform events. The expected sequence of events driven > from user space should be like the following. > > (1) Open the character device file > (2) Poll on the file for POLLIN event > (3) When unblocked, must attempt to read OPAL_PLAT_EVENT_MAX_SIZE size > (4) Kernel driver will pass at most one opal_plat_event structure > (5) Poll again for more new events
A few thoughts from discussing with Michael and Joel: - not convinced that a chardev is the most ideal way to notify userspace. It seems like yet-another powerpc specific notification mechanism, which isn't ideal. - netlink probably isn't right either (although maybe *sligthtly* better?) - it seems that the "standard" way is ACPI, so I wonder if we could emit an ACPI event and essentially fake having ACPI... that would make all existing userspace "just work", right? Looking at acpi_bus_generate_netlink_event call in drivers/acpi/button.c it looks possible that we may be able to (relatively simply) do that? - What do UPSs do? It would seem that some common "this is what's about to happen to your power" would almost *have* to exist somewhat generically? I strongly advocate for anything that doesn't require custom userspace that's OPAL/POWER specific (that we then have to get into distros etc etc) _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
