ALSA: hdmi - support infoframe for DisplayPort
DisplayPort works mostly in the same way as HDMI, except that it expects a slightly different audio infoframe format. Citations from "HDA036-A: Display Port Support and HDMI Miscellaneous Corrections": The HDMI specification defines a data island packet with a header of 4 bytes (3 bytes content + 1 byte ECC) and packet body of 32 bytes (28 bytes content and 4 bytes ECC). Display Port specification on the other hand defines a data island packet (secondary data packet) with header of 4 bytes protected by 4 bytes of parity, and data of theoretically up to 1024 bytes with each 16 bytes chunk of data protected by 4 bytes of parity. Note that the ECC or parity bytes are not present in the DIP content populated by software and are hardware generated. It tests DP connection based on the ELD conn_type field, which will be set by the graphics driver and can be overriden manually by users through the /proc/asound/card0/eld* interface. The DP infoframe is tested OK on Intel SandyBridge/CougarPoint platform. Signed-off-by:Wu Fengguang <fengguang.wu@intel.com> Signed-off-by:
Takashi Iwai <tiwai@suse.de>
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