Messages in this thread | | | Date | Mon, 02 Mar 2015 21:21:45 +0100 | From | Javier Martinez Canillas <> | Subject | Re: [PATCH] regulator: core: Fix enable GPIO reference counting |
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Hello Mark,
On 03/02/2015 07:57 PM, Mark Brown wrote: > On Fri, Feb 27, 2015 at 10:01:23PM +0100, Javier Martinez Canillas wrote: > >> I noticed the same problem in regulator_suspend_finish() when I was working >> on S2R for Exynos a couple of months ago and had patch [0] on my local tree >> but never found the time to do extensive testing so I never posted it. > > Please don't bury patches in the middle of mails where they're hard to > apply if they're useful. >
Sorry, if my intention was you to apply the patch then I would had posted it properly. But what I wanted was to share that I had the same issue and my approach to see if that also fixed Doug's issue.
Otherwise is hard to maintain a conversation across different threads.
>> I see that the check is already in _regulator_enable() so another option >> is to call _regulator_enable() instead of _regulator_do_enable() in >> regulator_suspend_finish(). > > I'm not entirely sure what "the check" is? >
The check I was referring to is _regulator_is_enabled() but now looking again I see that _regulator_enable() can't be used in regulator_suspend_finish() because that will increment the reference counting which is wrong.
>> Trying to enable an already enabled regulator may cause issues so is >> better to skip enabling regulators that were not disabled before suspend. > >> mutex_lock(&rdev->mutex); >> if (rdev->use_count > 0 || rdev->constraints->always_on) { >> - error = _regulator_do_enable(rdev); >> - if (error) >> - ret = error; >> + if (!_regulator_is_enabled(rdev)) { >> + error = _regulator_do_enable(rdev); >> + if (error) >> + ret = error; >> + } > > This seems like a better fix or at least a better approach - essentially > the assumption in most of the code is that regulator enables are just > register writes so repeated updates don't have any effect. We may need
Which doesn't seem to be the case for all regulators since at least I got failures when a FET in the tps65090 pmu was tried to be enabled twice.
> a specific per client count here... I've not looked at the code and I
Sorry, I'm not sure I understood what you meant. The suspend path:
suspend_prepare() -> suspend_set_state() -> .set_suspend_*
doesn't decrement use_count so is correct to call _regulator_do_enable() directly. The problem is the assumption that all regulators were either disabled on suspend or that enabling an enabled regulator is a no-op.
I'll post as a proper patch so you can review it.
Best regards, Javier
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