drm: rp1: rp1-vec: For progressive NTSC use 263 lines rather than 262

For NTSC, using an odd total number of lines inverts the colour phase
between successive frames, which ameliorates false colour artifacts,
although it slightly reduces frame rate from 60.05 Hz to 59.83 Hz.
Progressive DRM modes with 262 lines remain supported.

Signed-off-by: Nick Hollinghurst <[email protected]>

Author: njhollinghurst

drivers/gpu/drm/rp1/rp1-vec/rp1_vec.c

@@ -358,7 +358,9 @@ static int rp1vec_connector_get_modes(struct drm_connector *connector)
 				mode->vdisplay	  >>= 1;
 				mode->vsync_start >>= 1;
 				mode->vsync_end	  >>= 1;
-				mode->vtotal	  >>= 1;
+				mode->vtotal      >>= 1;
+				if (mode->vtotal == 262 && tvstd <= DRM_MODE_TV_MODE_PAL)
+					mode->vtotal++;
 			} else if (mode->hdisplay == 704 && mode->vtotal == preferred_lines) {
 				mode->type |= DRM_MODE_TYPE_PREFERRED;
 			}