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)));