[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>

1 files changed, 7 insertions, 8 deletions

diff --git a/sound/isa/ad1848/ad1848_lib.c b/sound/isa/ad1848/ad1848_lib.c
index f01e564b1238..d454d11989f0 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) {