Messages in this thread | | | From | Geert Uytterhoeven <> | Date | Mon, 23 Apr 2018 11:32:13 +0200 | Subject | Re: [PATCH/RFC 1/2] PM / wakeup: Add callback for wake-up change notification |
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Hi Rafael,
On Mon, Apr 23, 2018 at 11:18 AM, Rafael J. Wysocki <rjw@rjwysocki.net> wrote: > On Wednesday, March 14, 2018 12:26:24 PM CEST Geert Uytterhoeven wrote: >> Add a callback to inform a device that his wake-up setting has been >> changed. This allows a device to synchronize device configuration with >> an external user action. >> >> E.g. on systems using a Rohm BD9571MWV PMIC and a toggle accessory power >> switch, the system suspend procedure is: >> 1. Configure PMIC for DDR backup mode, which changes the role of the >> accessory power switch from a power to a wake-up switch, >> 2. Switch accessory power switch off, to prepare for system suspend, >> 3. Suspend system. >> >> Hence step 1 cannot be done in the PMIC's suspend callback, > > I don't quite understand this, so can you please explain? > > What can't it be done from ->prepare() or even from a suspend notifier? > >> but it can be done in the new callback, in response to the user writing "enabled" >> to the PMIC's wakeup virtual file in sysfs.
Step 2 (flip a switch on the board) is a manual step, to be done by the user. So it cannot be done from any suspend callback or notifier.
Gr{oetje,eeting}s,
Geert
-- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds
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