MPC5200B AC97 support for recent kernel
From: Juergen Beisert <hidden>
Date: 2008-02-07 14:52:03
Hi, I'm using a 2.6.23 kernel and trying to get the AC97 running on my MPC5200B= =20 based CPU card. I'm using a patch stack posted here last year. FEC and ATA= =20 seems running correctly. Also the AC97 seems to run, but I can hear some=20 noise only. But ALSA does detect the external Wolfson codec and its=20 capabilities correctly, so I think the AC97 link works as expected. Some things I noticed: - I can control the volume of the noise with alsamixer - the external codes outputs the correct clock (~12 MHz) - the MPC5200B AC97 driver receives interrupts from the bestcomm unit (to report progress to the pcm framework) - everything seems ways too fast. A four minutes mp3 song is ready after 40 seconds - I'm not sure: What type of data wants the AC97 PCS unit? AC97 data slots are 20 bits wide. int32_t or 24 bits per sample? Big endian? - does it use interleave? Left, right, left, right, ... to be fed into AC97 data slot 3 and 4? Any ideas? Juergen =2D-=20 Dipl.-Ing. Juergen Beisert | http://www.pengutronix.de =A0Pengutronix - Linux Solutions for Science and Industry =A0 Handelsregister: Amtsgericht Hildesheim, HRA 2686 =A0 =A0 =A0 Vertretung Sued/Muenchen, Germany Phone: +49-8766-939 228 | Fax: +49-5121-206917-9