[PATCH 1/5] drm/omap: Fix suspend resume regression after platform data removal

[Tomi Valkeinen]

Hi Tony,

On 31/05/2020 22:39, Tony Lindgren wrote:
> When booting without legacy platform data, we no longer have omap_device
> calling PM runtime suspend for us on suspend. This causes the driver
> context not be saved as we have no suspend and resume functions defined.
> 
> Let's fix the issue by switching over to use UNIVERSAL_DEV_PM_OPS as it
> will call the existing PM runtime suspend functions on suspend.

I don't think we can use UNIVERSAL_DEV_PM_OPS, as we can't disable DSS modules in any order, but 
things have to be shut down in orderly manner.

omapdrm hasn't relied on omap_device calling runtime suspend for us (I didn't know it does that). We 
have system suspend hooks in omap_drv.c:

SIMPLE_DEV_PM_OPS(omapdrm_pm_ops, omap_drm_suspend, omap_drm_resume)

omap_drm_suspend() is supposed to turn off the displays, which then cause dispc_runtime_put (and 
other runtime_puts) to be called, which result in dispc_runtime_suspend (and other runtime PM suspends).

So... For some reason that's no longer happening? I need to try to find a board with which 
suspend/resume works (without DSS)...

  Tomi

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