This commit fix out of specification about the value of FDF field in out packet
with 'no data'. This affects blocking mode.
According to IEC 61883-6, there is two way to generate AMDTP packets include no
data in blocking mode.
Way 1. an empty packet defined in IEC 61883-1
- Size of packet is 2 quadlets.
- The value of FDF is sfc.
- The packet includes only CIP headers
Way 2. a special non-empty packet defined in IEC 61883-6
- Size of packet is following to blocking mode
- The value of FDF is 0xff. This value is 'NO-DATA'. This means 'The receiver'
must ignore all the data in a CIP with this FDF code'.
- The packet includes dummy data.
But current implementation is a combination of them.
- Size of packet is 2 (way 1)
- FDF = 0xff (way 2)
This causes BeBoB chipset cannot sound.
This patch applies Way 1.
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Cc: Acked-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
82755abfe8