Messages in this thread | | | Subject | Re: [PATCH v4 01/15] ARM: export arm_pm_restart() | From | Lubomir Rintel <> | Date | Wed, 09 Jan 2019 08:24:04 +0100 |
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On Tue, 2019-01-08 at 23:31 +0000, Russell King - ARM Linux wrote: > On Tue, Jan 08, 2019 at 06:58:04PM +0100, Lubomir Rintel wrote: > > The OLPC XO 1.75 laptop is rebooted with a command to the Embedded > > Controller. The EC driver should be a module, since most people don't need > > it to be compiled in. > > Why do you need this - is there a reason why you can't hook onto the > restart_handler_list using register_restart_handler()? The registered > handlers are passed the command.
Actually, yes. The restart handlers are invoked in atomic context, but the EC communication needs to block. (The 1.75 EC is actually a SPI master: a command it initiated by poking a GPIO and waiting until EC tells us it's ready to read a command.)
Sorry for not mentioning that earlier, I forgot that it is the case.
> I would rather this is not exported to modules, it is generally unsafe > to hook stuff by directly poking function pointers from module code.
Lubo
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