[PATCH 4.17 011/324] drm/bridge/sii8620: fix display modes validation

[Greg Kroah-Hartman]

4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Maciej Purski <m.purski@xxxxxxxxxxx>

[ Upstream commit ecba7cfa3afbe489288f2c819158b7402afd7ee9 ]

Current implementation of mode_valid() and mode_fixup() callbacks
handle packed pixel modes improperly.

Fix it by using proper maximum clock values from the documentation.

Signed-off-by: Maciej Purski <m.purski@xxxxxxxxxxx>
Signed-off-by: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/1517568865-25219-1-git-send-email-m.purski@xxxxxxxxxxx
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/bridge/sil-sii8620.c |   78 +++++++++++++++++------------------
 1 file changed, 40 insertions(+), 38 deletions(-)

--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -36,8 +36,11 @@
 
 #define SII8620_BURST_BUF_LEN 288
 #define VAL_RX_HDMI_CTRL2_DEFVAL VAL_RX_HDMI_CTRL2_IDLE_CNT(3)
-#define MHL1_MAX_LCLK 225000
-#define MHL3_MAX_LCLK 600000
+
+#define MHL1_MAX_PCLK 75000
+#define MHL1_MAX_PCLK_PP_MODE 150000
+#define MHL3_MAX_PCLK 200000
+#define MHL3_MAX_PCLK_PP_MODE 300000
 
 enum sii8620_mode {
 	CM_DISCONNECTED,
@@ -2277,17 +2280,43 @@ static void sii8620_detach(struct drm_br
 	rc_unregister_device(ctx->rc_dev);
 }
 
+static int sii8620_is_packing_required(struct sii8620 *ctx,
+				       const struct drm_display_mode *mode)
+{
+	int max_pclk, max_pclk_pp_mode;
+
+	if (sii8620_is_mhl3(ctx)) {
+		max_pclk = MHL3_MAX_PCLK;
+		max_pclk_pp_mode = MHL3_MAX_PCLK_PP_MODE;
+	} else {
+		max_pclk = MHL1_MAX_PCLK;
+		max_pclk_pp_mode = MHL1_MAX_PCLK_PP_MODE;
+	}
+
+	if (mode->clock < max_pclk)
+		return 0;
+	else if (mode->clock < max_pclk_pp_mode)
+		return 1;
+	else
+		return -1;
+}
+
 static enum drm_mode_status sii8620_mode_valid(struct drm_bridge *bridge,
 					 const struct drm_display_mode *mode)
 {
 	struct sii8620 *ctx = bridge_to_sii8620(bridge);
+	int pack_required = sii8620_is_packing_required(ctx, mode);
 	bool can_pack = ctx->devcap[MHL_DCAP_VID_LINK_MODE] &
 			MHL_DCAP_VID_LINK_PPIXEL;
-	unsigned int max_pclk = sii8620_is_mhl3(ctx) ? MHL3_MAX_LCLK :
-						       MHL1_MAX_LCLK;
-	max_pclk /= can_pack ? 2 : 3;
 
-	return (mode->clock > max_pclk) ? MODE_CLOCK_HIGH : MODE_OK;
+	switch (pack_required) {
+	case 0:
+		return MODE_OK;
+	case 1:
+		return (can_pack) ? MODE_OK : MODE_CLOCK_HIGH;
+	default:
+		return MODE_CLOCK_HIGH;
+	}
 }
 
 static bool sii8620_mode_fixup(struct drm_bridge *bridge,
@@ -2295,43 +2324,16 @@ static bool sii8620_mode_fixup(struct dr
 			       struct drm_display_mode *adjusted_mode)
 {
 	struct sii8620 *ctx = bridge_to_sii8620(bridge);
-	int max_lclk;
-	bool ret = true;
 
 	mutex_lock(&ctx->lock);
 
-	max_lclk = sii8620_is_mhl3(ctx) ? MHL3_MAX_LCLK : MHL1_MAX_LCLK;
-	if (max_lclk > 3 * adjusted_mode->clock) {
-		ctx->use_packed_pixel = 0;
-		goto end;
-	}
-	if ((ctx->devcap[MHL_DCAP_VID_LINK_MODE] & MHL_DCAP_VID_LINK_PPIXEL) &&
-	    max_lclk > 2 * adjusted_mode->clock) {
-		ctx->use_packed_pixel = 1;
-		goto end;
-	}
-	ret = false;
-end:
-	if (ret) {
-		u8 vic = drm_match_cea_mode(adjusted_mode);
+	ctx->use_packed_pixel = sii8620_is_packing_required(ctx, adjusted_mode);
+	ctx->video_code = drm_match_cea_mode(adjusted_mode);
+	ctx->pixel_clock = adjusted_mode->clock;
 
-		if (!vic) {
-			union hdmi_infoframe frm;
-			u8 mhl_vic[] = { 0, 95, 94, 93, 98 };
-
-			/* FIXME: We need the connector here */
-			drm_hdmi_vendor_infoframe_from_display_mode(
-				&frm.vendor.hdmi, NULL, adjusted_mode);
-			vic = frm.vendor.hdmi.vic;
-			if (vic >= ARRAY_SIZE(mhl_vic))
-				vic = 0;
-			vic = mhl_vic[vic];
-		}
-		ctx->video_code = vic;
-		ctx->pixel_clock = adjusted_mode->clock;
-	}
 	mutex_unlock(&ctx->lock);
-	return ret;
+
+	return true;
 }
 
 static const struct drm_bridge_funcs sii8620_bridge_funcs = {