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Patch "video/hdmi: Allow "empty" HDMI infoframes" has been added to the 4.15-stable tree

PATCH [email protected] 1 participant 1 message Mar 16, 2018

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This is a note to let you know that I've just added the patch titled

video/hdmi: Allow "empty" HDMI infoframes

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
video-hdmi-allow-empty-hdmi-infoframes.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From foo@baz Fri Mar 16 15:11:07 CET 2018

From: "Ville Syrj�l�" <[email protected]>
Date: Mon, 13 Nov 2017 19:04:18 +0200
Subject: video/hdmi: Allow "empty" HDMI infoframes

From: "Ville Syrj�l�" <[email protected]>

[ Upstream commit 593f4b19a094c4426bd1e1e3cbab87a48bd13c71 ]

HDMI 2.0 Appendix F suggest that we should keep sending the infoframe when switching from 3D to 2D mode, even if the infoframe isn't strictly necessary (ie. not needed to transmit the VIC or stereo information). This is a workaround against some sinks that fail to realize that they should switch from 3D to 2D mode when the source stop transmitting the infoframe.

v2: Handle unpack() as well
Pull the length calculation into a helper

---
 drivers/video/hdmi.c |   51 +++++++++++++++++++++++++++++++--------------------
 1 file changed, 31 insertions(+), 20 deletions(-)
drivers/video/hdmi.c +31 -20
@@ -321,6 +321,17 @@ int hdmi_vendor_infoframe_init(struct hd
 }
 EXPORT_SYMBOL(hdmi_vendor_infoframe_init);
 
+static int hdmi_vendor_infoframe_length(const struct hdmi_vendor_infoframe *frame)
+{
+	/* for side by side (half) we also need to provide 3D_Ext_Data */
+	if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
+		return 6;
+	else if (frame->vic != 0 || frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID)
+		return 5;
+	else
+		return 4;
+}
+
 /**
  * hdmi_vendor_infoframe_pack() - write a HDMI vendor infoframe to binary buffer
  * @frame: HDMI infoframe
@@ -341,19 +352,11 @@ ssize_t hdmi_vendor_infoframe_pack(struc
 	u8 *ptr = buffer;
 	size_t length;
 
-	/* empty info frame */
-	if (frame->vic == 0 && frame->s3d_struct == HDMI_3D_STRUCTURE_INVALID)
-		return -EINVAL;
-
 	/* only one of those can be supplied */
 	if (frame->vic != 0 && frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID)
 		return -EINVAL;
 
-	/* for side by side (half) we also need to provide 3D_Ext_Data */
-	if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
-		frame->length = 6;
-	else
-		frame->length = 5;
+	frame->length = hdmi_vendor_infoframe_length(frame);
 
 	length = HDMI_INFOFRAME_HEADER_SIZE + frame->length;
 
@@ -372,14 +375,16 @@ ssize_t hdmi_vendor_infoframe_pack(struc
 	ptr[5] = 0x0c;
 	ptr[6] = 0x00;
 
-	if (frame->vic) {
-		ptr[7] = 0x1 << 5;	/* video format */
-		ptr[8] = frame->vic;
-	} else {
+	if (frame->s3d_struct != HDMI_3D_STRUCTURE_INVALID) {
 		ptr[7] = 0x2 << 5;	/* video format */
 		ptr[8] = (frame->s3d_struct & 0xf) << 4;
 		if (frame->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF)
 			ptr[9] = (frame->s3d_ext_data & 0xf) << 4;
+	} else if (frame->vic) {
+		ptr[7] = 0x1 << 5;	/* video format */
+		ptr[8] = frame->vic;
+	} else {
+		ptr[7] = 0x0 << 5;	/* video format */
 	}
 
 	hdmi_infoframe_set_checksum(buffer, length);
@@ -1165,7 +1170,7 @@ hdmi_vendor_any_infoframe_unpack(union h
 
 	if (ptr[0] != HDMI_INFOFRAME_TYPE_VENDOR ||
 	    ptr[1] != 1 ||
-	    (ptr[2] != 5 && ptr[2] != 6))
+	    (ptr[2] != 4 && ptr[2] != 5 && ptr[2] != 6))
 		return -EINVAL;
 
 	length = ptr[2];
@@ -1193,16 +1198,22 @@ hdmi_vendor_any_infoframe_unpack(union h
 
 	hvf->length = length;
 
-	if (hdmi_video_format == 0x1) {
-		hvf->vic = ptr[4];
-	} else if (hdmi_video_format == 0x2) {
+	if (hdmi_video_format == 0x2) {
+		if (length != 5 && length != 6)
+			return -EINVAL;
 		hvf->s3d_struct = ptr[4] >> 4;
 		if (hvf->s3d_struct >= HDMI_3D_STRUCTURE_SIDE_BY_SIDE_HALF) {
-			if (length == 6)
-				hvf->s3d_ext_data = ptr[5] >> 4;
-			else
+			if (length != 6)
 				return -EINVAL;
+			hvf->s3d_ext_data = ptr[5] >> 4;
 		}
+	} else if (hdmi_video_format == 0x1) {
+		if (length != 5)
+			return -EINVAL;
+		hvf->vic = ptr[4];
+	} else {
+		if (length != 4)
+			return -EINVAL;
 	}
 
 	return 0;

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/drm-vblank-fix-vblank-timestamp-debugs.patch queue-4.15/video-hdmi-allow-empty-hdmi-infoframes.patch queue-4.15/drm-edid-set-eld-connector-type-in-drm_edid_to_eld.patch