drm/stm: dsi: higher pll out only in video burst mode

In order to better support video non-burst modes,
the +20% on pll out is added only in burst mode.
Signed-off-by: Philippe Cornu <philippe.cornu@st.com>
Signed-off-by: Yannick Fertré <yannick.fertre@st.com>
Reviewed-by: Yannick Fertré <yannick.fertre@st.com>
Signed-off-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/1568278589-20400-1-git-send-email-yannick.fertre@st.com

drivers/gpu/drm/stm/dw_mipi_dsi-stm.c

@@ -260,8 +260,11 @@ dw_mipi_dsi_get_lane_mbps(void *priv_data, const struct drm_display_mode *mode,
 	/* Compute requested pll out */
 	bpp = mipi_dsi_pixel_format_to_bpp(format);
 	pll_out_khz = mode->clock * bpp / lanes;
+
 	/* Add 20% to pll out to be higher than pixel bw (burst mode only) */
-	pll_out_khz = (pll_out_khz * 12) / 10;
+	if (mode_flags & MIPI_DSI_MODE_VIDEO_BURST)
+		pll_out_khz = (pll_out_khz * 12) / 10;
+
 	if (pll_out_khz > dsi->lane_max_kbps) {
 		pll_out_khz = dsi->lane_max_kbps;
 		DRM_WARN("Warning max phy mbps is used\n");