On Thu, Apr 21, 2016 at 10:57 PM, Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> wrote: > Hi Rafael, > > On Thursday 21 Apr 2016 21:52:56 Rafael J. Wysocki wrote: >> On Thursday, April 21, 2016 02:52:55 AM Laurent Pinchart wrote: >> > The pm_runtime_force_suspend() and pm_runtime_force_resume() helpers are >> > designed to help driver being RPM-centric by offering an easy way to >> > manage runtime PM state during system suspend and resume. The first >> > function will force the device into runtime suspend at system suspend >> > time, while the second one will perform the reverse operation at system >> > resume time. >> > >> > However, the pm_runtime_force_resume() really forces resume, regardless >> > of whether the device was running or already suspended before the call >> > to pm_runtime_force_suspend(). This results in devices being runtime >> > resumed at system resume time when they shouldn't. >> > >> > Fix this by recording whether the device has been forcefully suspended >> > in pm_runtime_force_suspend() and condition resume in >> > pm_runtime_force_resume() to that state. >> > >> > All current users of pm_runtime_force_resume() call the function >> > unconditionally in their system resume handler (some actually set it as >> > the resume handler), all after calling pm_runtime_force_suspend() at >> > system suspend time. The change in behaviour should thus be safe. >> > >> > Signed-off-by: Laurent Pinchart >> > <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx> >> > Reviewed-by: Kevin Hilman <khilman@xxxxxxxxxxxx> >> >> Ulf, any comments? > > Ulf has proposed a different approach in "[PATCH] PM / Runtime: Defer resuming > of the device in pm_runtime_force_resume()". I agree that using usage_count is > better than introducing a new state flag in struct dev_pm_info, with a caveat: > it doesn't work properly :-). We would have to fix genpd first, as commented > in a reply to Ulf's patch. OK, thanks! Since I'd prefer to avoid adding more state flags too, I'll let you guys noodle around this for a while more. :-)
