CVS commit: src/sys/dev/ic

[Steve Woodford <scw%netbsd.org@localhost>]

Module Name:    src
Committed By:   scw
Date:           Wed May 11 13:13:11 UTC 2005

Modified Files:
        src/sys/dev/ic: ac97.c

Log Message:
Add a heuristic to test if an audio CODEC's AC97_REG_POWER register supports
the AC97_POWER_ANL bit.

The heuristic simply checks if AC97_REG_POWER's AC97_POWER_MIXER  bit can
be set, implying the CODEC can control power to its mixer. If the bit
reads back as zero after we set it, assume ANL is reserved.

Without this patch, some CODECs (e.g. Philips UCB1400) will experience long
delays during attach and resume while the driver waits for a bit which will
never set.

Thanks to jmcneill@ for reviewing this WRT AC97 modem power control.


To generate a diff of this commit:
cvs rdiff -r1.73 -r1.74 src/sys/dev/ic/ac97.c

Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.