RADEON_GRPH_BUFFER_CNTL
temp = RREG32(RADEON_GRPH_BUFFER_CNTL);
WREG32(RADEON_GRPH_BUFFER_CNTL, ((temp & ~RADEON_GRPH_CRITICAL_POINT_MASK) |
(unsigned int)RREG32(RADEON_GRPH_BUFFER_CNTL));