[alsa-devel] [PATCH] ad1838/cs4231 -- fix MCE timeout upon initial load

Rene Herman rene.herman at gmail.com
Mon Sep 10 20:29:21 CEST 2007

Hi Takashi.

When the ad1848/cs2431 is first being initialized, auto-calibration may not 
be set causing a timeout waiting for it in snd_ad1848/cs4231_mce_down().

This has no dire consequences other than an alarming printk, but since what 
we need to wait for is for the calibration to _finish_, let's just check for 
that instead.

The early chips need a slight delay (as commented -- 5 sample periods) to be 
sure that _if_ calibration is going to happen, it has started when we check 
While the CS4231A datasheet implies it'll happen immediately on downing MCE, 
some testing is showing that there's a window there as well, so just do the 
delay everywhere.

Thanks to Krysztof Helt for pinpointing this problem.

Signed-off-by: Rene Herman <rene.herman at gmail.com>

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