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In order to ensure that our system suspend and resume callbacks are called in the correct order wrt. those of the HDA driver add a device link to the HDA driver during audio component binding time. With i915 as the supplier and HDA as the consumer the PM framework will guarantee the HDA->i915 suspend (and shutdown) and i915->HDA resume order. Atm, the lack of this ordering is not a problem, since all the i915 suspend/resume steps that need to be ordered wrt. the HDA driver's suspend/resume steps are separated out to the i915 suspend_late/resume_early hooks. That will change in a follow-up patchset where we'll need this ordering guarantee for steps that are in the i915 suspend/resume hooks (and which can't be moved to suspend_late/resume_early for other reasons). So this patch is a preparation for that follow-up patchset. The change also allows us to move towards removing the i915 suspend_late/resume_early hooks alltogether. Since we only need to ensure the ordering during suspend/resume and not during driver probing create the link with DL_FLAG_STATELESS. Since the probe time ordering has to be optional we use the component framework for that. Similarly for runtime PM we depend on the audio driver getting/putting an i915 runtime PM reference whenever it needs it (along with the proper i915 display power domain) via the audio component ops get_power / put_power hooks. So we create the device link without DL_FLAG_PM_RUNTIME. v2: (Ville) - Add a note to the commit message about not using the device link runtime PM ordering. - Handle the error return from device_link_add(). Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Cc: Takashi Iwai <tiwai@suse.de> Cc: Lukas Wunner <lukas@wunner.de> Signed-off-by: Imre Deak <imre.deak@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20181023144310.8272-1-imre.deak@intel.com
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