Errata i631 description: "When in YUV4:2:0 format in 1D burst, the DISPC DMA skips lines when fetching Chroma sampling." Workaround: "If YUV4:2:0-1D burst is required: Set DISPC_VIDp_ATTRIBUTES[22]DOUBLESTRIDE to 0x0 and DISPC_VIDp_ATTRIBUTES[13:12]ROTATION to 0x1 or 0x3" The description is somewhat confusing, but testing has shown that DSS fetches extra rows from memory when using NV12 format in 1D mode. If the memory after the framebuffer is inaccessible, this leads to OCP errors. The driver always uses DOUBLESTRIDE=0 when using 1D mode, so we only need to handle the ROTATION part. The issue exist on all OMAP4 and OMAP5 based DSS IPs. Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxx> --- drivers/video/fbdev/omap2/dss/dispc.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/drivers/video/fbdev/omap2/dss/dispc.c b/drivers/video/fbdev/omap2/dss/dispc.c index f4fc77d9d3bf..a074d8b70591 100644 --- a/drivers/video/fbdev/omap2/dss/dispc.c +++ b/drivers/video/fbdev/omap2/dss/dispc.c @@ -1741,6 +1741,15 @@ static void dispc_ovl_set_rotation_attrs(enum omap_plane plane, u8 rotation, row_repeat = false; } + /* + * OMAP4/5 Errata i631: + * NV12 in 1D mode must use ROTATION=1. Otherwise DSS will fetch extra + * rows beyond the framebuffer, which may cause OCP error. + */ + if (color_mode == OMAP_DSS_COLOR_NV12 && + rotation_type != OMAP_DSS_ROT_TILER) + vidrot = 1; + REG_FLD_MOD(DISPC_OVL_ATTRIBUTES(plane), vidrot, 13, 12); if (dss_has_feature(FEAT_ROWREPEATENABLE)) REG_FLD_MOD(DISPC_OVL_ATTRIBUTES(plane), -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
