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Diffstat (limited to 'sound/isa/ad1848')
-rw-r--r--sound/isa/ad1848/ad1848_lib.c57
1 files changed, 21 insertions, 36 deletions
diff --git a/sound/isa/ad1848/ad1848_lib.c b/sound/isa/ad1848/ad1848_lib.c
index 18355fd66cb5..21536b7de608 100644
--- a/sound/isa/ad1848/ad1848_lib.c
+++ b/sound/isa/ad1848/ad1848_lib.c
@@ -203,9 +203,8 @@ static void snd_ad1848_mce_up(struct snd_ad1848 *chip)
static void snd_ad1848_mce_down(struct snd_ad1848 *chip)
{
- unsigned long flags;
- int timeout;
- unsigned long end_time;
+ unsigned long flags, timeout;
+ int reg;
spin_lock_irqsave(&chip->reg_lock, flags);
for (timeout = 5; timeout > 0; timeout--)
@@ -222,50 +221,36 @@ static void snd_ad1848_mce_down(struct snd_ad1848 *chip)
#endif
chip->mce_bit &= ~AD1848_MCE;
- timeout = inb(AD1848P(chip, REGSEL));
- outb(chip->mce_bit | (timeout & 0x1f), AD1848P(chip, REGSEL));
- if (timeout == 0x80)
+ reg = inb(AD1848P(chip, REGSEL));
+ outb(chip->mce_bit | (reg & 0x1f), AD1848P(chip, REGSEL));
+ if (reg == 0x80)
snd_printk(KERN_WARNING "mce_down [0x%lx]: serious init problem - codec still busy\n", chip->port);
- if ((timeout & AD1848_MCE) == 0) {
+ if ((reg & AD1848_MCE) == 0) {
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.
+ * Wait for auto-calibration (AC) process to finish, i.e. ACI to go low.
+ * It may take up to 5 sample periods (at most 907 us @ 5.5125 kHz) for
+ * the process to _start_, so it is important to wait at least that long
+ * before checking. Otherwise we might think AC has finished when it
+ * has in fact not begun. It could take 128 (no AC) or 384 (AC) cycles
+ * for ACI to drop. This gives a wait of at most 70 ms with a more
+ * typical value of 3-9 ms.
*/
- spin_unlock_irqrestore(&chip->reg_lock, flags);
- msleep(1);
- spin_lock_irqsave(&chip->reg_lock, flags);
-
- snd_printdd("(2) jiffies = %lu\n", jiffies);
-
- end_time = jiffies + msecs_to_jiffies(250);
- while (snd_ad1848_in(chip, AD1848_TEST_INIT) & AD1848_CALIB_IN_PROGRESS) {
+ timeout = jiffies + msecs_to_jiffies(250);
+ do {
spin_unlock_irqrestore(&chip->reg_lock, flags);
- if (time_after(jiffies, end_time)) {
- snd_printk(KERN_ERR "mce_down - auto calibration time out (2)\n");
- return;
- }
msleep(1);
spin_lock_irqsave(&chip->reg_lock, flags);
- }
-
- snd_printdd("(3) jiffies = %lu\n", jiffies);
-
- end_time = jiffies + msecs_to_jiffies(100);
- while (inb(AD1848P(chip, REGSEL)) & AD1848_INIT) {
- spin_unlock_irqrestore(&chip->reg_lock, flags);
- if (time_after(jiffies, end_time)) {
- snd_printk(KERN_ERR "mce_down - auto calibration time out (3)\n");
- return;
- }
- msleep(1);
- spin_lock_irqsave(&chip->reg_lock, flags);
- }
+ reg = snd_ad1848_in(chip, AD1848_TEST_INIT) &
+ AD1848_CALIB_IN_PROGRESS;
+ } while (reg && time_before(jiffies, timeout));
spin_unlock_irqrestore(&chip->reg_lock, flags);
+ if (reg)
+ snd_printk(KERN_ERR
+ "mce_down - auto calibration time out (2)\n");
snd_printdd("(4) jiffies = %lu\n", jiffies);
snd_printd("mce_down - exit = 0x%x\n", inb(AD1848P(chip, REGSEL)));