V4L/DVB (4987): Improve cx2341x documentation

Document the program index table format, removed unused interrupt documentation
and improve the documentation regarding the audio mode (stereo/joint/dual/mono).

Signed-off-by: Hans Verkuil <hverkuil@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>

1 files changed, 20 insertions, 4 deletions

diff --git a/Documentation/video4linux/cx2341x/fw-encoder-api.txt b/Documentation/video4linux/cx2341x/fw-encoder-api.txt
index 2412718c3d0b..fe02bdb84598 100644
--- a/Documentation/video4linux/cx2341x/fw-encoder-api.txt
+++ b/Documentation/video4linux/cx2341x/fw-encoder-api.txt
@@ -322,9 +322,7 @@ Param[0]
                 '01'=JointStereo
                 '10'=Dual
                 '11'=Mono
-                Note: testing seems to indicate that Mono and possibly
-                JointStereo are not working (default to stereo).
-                Dual does work, though.
+                Note: the cx23415 cannot decode Joint Stereo properly.
 
           10:11 Mode Extension used in joint_stereo mode.
                 In Layer I and II they indicate which subbands are in
@@ -403,16 +401,34 @@ Name 	CX2341X_ENC_SET_PGM_INDEX_INFO
 Enum    199/0xC7
 Description
         Sets the Program Index Information.
+        The information is stored as follows:
+
+        struct info {
+                u32 length;             // Length of this frame
+                u32 offset_low;         // Offset in the file of the
+                u32 offset_high;        // start of this frame
+                u32 mask1;              // Bits 0-1 are the type mask:
+                                        // 1=I, 2=P, 4=B
+                u32 pts;                // The PTS of the frame
+                u32 mask2;              // Bit 0 is bit 32 of the pts.
+        };
+        u32 table_ptr;
+        struct info index[400];
+
+        The table_ptr is the encoder memory address in the table were
+        *new* entries will be written. Note that this is a ringbuffer,
+        so the table_ptr will wraparound.
 Param[0]
         Picture Mask:
             0=No index capture
             1=I frames
             3=I,P frames
             7=I,P,B frames
+        (Seems to be ignored, it always indexes I, P and B frames)
 Param[1]
         Elements requested (up to 400)
 Result[0]
-        Offset in SDF memory of the table.
+        Offset in the encoder memory of the start of the table.
 Result[1]
         Number of allocated elements up to a maximum of Param[1]