drm/i915: Shut down displays gracefully on reboot
Implement the pci .shutdown() hook in order to quiesce the hardware prior to reboot. The main purpose here is to turn all displays off. Some displays/other drivers tend to get confused if the state after reboot isn't exactly as they expected. One specific example was the Dell UP2414Q in MST mode. It would require me to pull the power cord after a reboot or else it would just not come back to life. Sadly I don't have that at hand anymore so not sure if it's still misbehaving without the graceful shutdown, or if we managed to fix something else since I last tested it. For good measure we do a gem suspend as well, so that we match the suspend flow more closely. Also stopping all DMA and whatnot is probably a good idea for kexec. I would expect that some kind of GT reset happens on normal reboot so probably not totally necessary there. v2: Use the pci .shutdown() hook instead of a reboot notifier (Lukas) Do the gem suspend for kexec (Chris) Cc: Lukas Wunner <lukas@wunner.de> Cc: Chris Wilson <chris@chris-wilson.co.uk> Signed-off-by:Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20201001151640.14590-1-ville.syrjala@linux.intel.com Reviewed-by:
Jani Nikula <jani.nikula@intel.com> Reviewed-by:
Chris Wilson <chris@chris-wilson.co.uk>
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67807f52
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