V_2PIX
if( v_display > V_2PIX(RADEON_CRTC_V_DISP >> RADEON_CRTC_V_DISP_SHIFT) - 5)
v_display = V_2PIX(RADEON_CRTC_V_DISP >> RADEON_CRTC_V_DISP_SHIFT) - 5;
if( v_sync_start > V_2PIX(RADEON_CRTC_V_SYNC_STRT) - 4)
v_sync_start = V_2PIX(RADEON_CRTC_V_SYNC_STRT) - 4;
if( v_total > V_2PIX( RADEON_CRTC_V_TOTAL ) ) {
v_total = V_2PIX( RADEON_CRTC_V_TOTAL );