Re: [PATCH v3 5/5] drm/arm/malidp: Added the late system pm functions

From: Daniel Vetter
Date: Wed Apr 25 2018 - 03:17:30 EST


On Tue, Apr 24, 2018 at 07:12:47PM +0100, Ayan Kumar Halder wrote:
> malidp_pm_suspend_late checks if the runtime status is not suspended
> and if so, invokes malidp_runtime_pm_suspend which disables the
> display engine/core interrupts and the clocks. It sets the runtime status
> as suspended.
>
> The difference between suspend() and suspend_late() is as follows:-
> 1. suspend() makes the device quiescent. In our case, we invoke the DRM
> helper which disables the CRTC. This would have invoked runtime pm
> suspend but the system suspend process disables runtime pm.
> 2. suspend_late() It continues the suspend operations of the drm device
> which was started by suspend(). In our case, it performs the same functionality
> as runtime_suspend().
>
> The complimentary functions are resume() and resume_early(). In the case of
> resume_early(), we invoke malidp_runtime_pm_resume() which enables the clocks
> and the interrupts. It sets the runtime status as active. If the device was
> in runtime suspend mode before system suspend was called, pm_runtime_work()
> will put the device back in runtime suspended mode( after the complete system
> has been resumed).
>
> Signed-off-by: Ayan Kumar Halder <ayan.halder@xxxxxxx>
>

Afaiui we still haven't bottomed out on the discussion on v1. Did you get
hold of Rafael?
-Daniel

> ---
> Changes in v3:-
> - Rebased on top of earlier v3 patches,
>
> Changes in v2:-
> - Removed the change id and modified the commit message
> ---
> drivers/gpu/drm/arm/malidp_drv.c | 17 +++++++++++++++++
> 1 file changed, 17 insertions(+)
>
> diff --git a/drivers/gpu/drm/arm/malidp_drv.c b/drivers/gpu/drm/arm/malidp_drv.c
> index 82221ea..c53b46a 100644
> --- a/drivers/gpu/drm/arm/malidp_drv.c
> +++ b/drivers/gpu/drm/arm/malidp_drv.c
> @@ -768,8 +768,25 @@ static int __maybe_unused malidp_pm_resume(struct device *dev)
> return 0;
> }
>
> +static int __maybe_unused malidp_pm_suspend_late(struct device *dev)
> +{
> + if (!pm_runtime_status_suspended(dev)) {
> + malidp_runtime_pm_suspend(dev);
> + pm_runtime_set_suspended(dev);
> + }
> + return 0;
> +}
> +
> +static int __maybe_unused malidp_pm_resume_early(struct device *dev)
> +{
> + malidp_runtime_pm_resume(dev);
> + pm_runtime_set_active(dev);
> + return 0;
> +}
> +
> static const struct dev_pm_ops malidp_pm_ops = {
> SET_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend, malidp_pm_resume) \
> + SET_LATE_SYSTEM_SLEEP_PM_OPS(malidp_pm_suspend_late, malidp_pm_resume_early) \
> SET_RUNTIME_PM_OPS(malidp_runtime_pm_suspend, malidp_runtime_pm_resume, NULL)
> };
>
> --
> 2.7.4
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch