drm: Remove dev_pm_ops from drm_class
The PM core introduced the ability to keep devices runtime suspended during the entire system suspend/resume process with commit aae4518b ("PM / sleep: Mechanism to avoid resuming runtime-suspended devices unnecessarily"). Before this so-called "direct-complete" procedure was introduced, devices were always runtime resumed only to be immediately put to sleep again using their ->suspend hook. Direct-complete is enabled by returning a positive value from the ->prepare hook. The PCI core usually does this automatically. Direct-complete is only available for a device if all children use it as well. Currently we cannot support direct-complete for DRM drivers because the DRM core automatically registers multiple DRM minors which belong to device class drm_class, and drm_class uses a struct dev_pm_ops which lacks the ->prepare callback. While this could be solved by adding the missing ->prepare callback, closer inspection shows that there are no DRM drivers left which declare the legacy ->suspend and ->resume callbacks in their drm_driver struct. The last ones to remove them were i915 with commit 1751fcf9 ("drm/i915: Fix module initialisation, v2.") and exynos with commit e7fefb1d ("drm/exynos: remove legacy ->suspend()/resume()"). Consequently the struct dev_pm_ops of drm_class is now dead code. Remove it. If no dev_pm_ops is declared for a device, the PM core automatically enables direct-complete for it, thereby making that mechanism available to the parent DRM PCI devices. Signed-off-by: NLukas Wunner <lukas@wunner.de> Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch> Link: http://patchwork.freedesktop.org/patch/msgid/da848fcd5ca72a35d9a722e644719977a47bb7ba.1465382836.git.lukas@wunner.de
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