Originally added in commit 1f84e550a870 ("drm/i915 more registers for S3 (DSPCLK_GATE_D, CACHE_MODE_0, MI_ARB_STATE)") to fix some underruns. I suspect that was due to the trickle feed settings getting clobbered during suspend. We've been disabling trickle feed explicitly since commit 20f949670f51 ("drm/i915: Disable trickle feed via MI_ARB_STATE for the gen4") so this magic save/restore should no longer be needed. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200908140210.31048-3-ville.syrjala@linux.intel.com Reviewed-by: Jani Nikula <jani.nikula@intel.com>