RADEON_HDP_APER_CNTL
WREG32_P(RADEON_HOST_PATH_CNTL, RADEON_HDP_APER_CNTL,
~RADEON_HDP_APER_CNTL);
if (RREG32(RADEON_HOST_PATH_CNTL) & RADEON_HDP_APER_CNTL)