Re: [PATCH 01/44] kernel: Add support for poweroff handler call chain

From: Philippe Rétornaz
Date: Tue Oct 07 2014 - 03:47:10 EST


Hello

This seems exactly what I would need on the mc13783 to handle cleanly the poweroff,
but after reading this patchset I have the following question:

[...]

+/*
+ * Notifier list for kernel code which wants to be called
+ * to power off the system.
+ */
+static ATOMIC_NOTIFIER_HEAD(poweroff_handler_list);

[...]

+void do_kernel_poweroff(void)
+{
+ atomic_notifier_call_chain(&poweroff_handler_list, 0, NULL);
+}
+

It seems that the poweroff callback needs to be atomic as per
_atomic_notifier_call_chain documentation:

"Calls each function in a notifier chain in turn. The functions
run in an atomic context"

But this is a problem for many MFD (mc13783, twl4030 etc ...) which are
accessible on only a blocking bus (SPI, I2C).

What I am missing here ?

Thanks,

Philippe
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