SCDC_TMDS_CONFIG
ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);
ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config);
ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);
ret = drm_scdc_writeb(adapter, SCDC_TMDS_CONFIG, config);
ret = drm_scdc_readb(adapter, SCDC_TMDS_CONFIG, &config);