diff options
| author | Rene Herman <rene.herman@gmail.com> | 2007-09-10 23:19:55 +0200 |
|---|---|---|
| committer | Jaroslav Kysela <perex@perex.cz> | 2007-10-16 16:49:24 +0200 |
| commit | 90cf9b853281a39555cce8a42fc0fabad75b42a8 (patch) | |
| tree | 45b1da8f46b35d5b7d3fd1e6fbf05518670ff920 /sound/isa/ad1848 | |
| parent | 51c80cb65ff9b7bdf172f9075138793c2bce6883 (diff) | |
[ALSA] ad1838/cs4231 - fix MCE timeout upon initial load
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@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
Diffstat (limited to 'sound/isa/ad1848')
| -rw-r--r-- | sound/isa/ad1848/ad1848_lib.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/sound/isa/ad1848/ad1848_lib.c b/sound/isa/ad1848/ad1848_lib.c index f01e564b123..d454d11989f 100644 --- a/sound/isa/ad1848/ad1848_lib.c +++ b/sound/isa/ad1848/ad1848_lib.c @@ -229,16 +229,15 @@ static void snd_ad1848_mce_down(struct snd_ad1848 *chip) spin_unlock_irqrestore(&chip->reg_lock, flags); return; } - /* calibration process */ - for (timeout = 500; timeout > 0 && (snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) == 0; timeout--); - if ((snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) == 0) { - snd_printd("mce_down - auto calibration time out (1)\n"); - spin_unlock_irqrestore(&chip->reg_lock, flags); - return; - } + /* + * Wait for (possible -- during init auto-calibration may not be set) + * calibration process to start. Needs upto 5 sample periods on AD1848 + * which at the slowest possible rate of 5.5125 kHz means 907 us. + */ + msleep(1); #if 0 - printk("(2) timeout = %i, jiffies = %li\n", timeout, jiffies); + printk("(2) jiffies = %li\n", jiffies); #endif time = HZ / 4; while (snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) { |