Ray Lee wrote:
> On Nov 7, 2007 10:34 AM, Roel Kluin <[email protected]> wrote:
>> If count reaches zero, the loop ends, but the postfix decrement subtracts it.
>> so, testing for 'count == 0' will not work.
>>
>> Signed-off-by: Roel Kluin <[email protected]>
>> ---
>> diff --git a/sound/oss/trident.c b/sound/oss/trident.c
>> index 96adc47..94b5fb4 100644
>> --- a/sound/oss/trident.c
>> +++ b/sound/oss/trident.c
>> @@ -2939,7 +2939,7 @@ trident_ac97_set(struct ac97_codec *codec, u8 reg, u16 val)
>>
>> data |= (mask | (reg & AC97_REG_ADDR));
>>
>> - if (count == 0) {
>> + if (count == -1) {
>> printk(KERN_ERR "trident: AC97 CODEC write timed out.\n");
>> spin_unlock_irqrestore(&card->lock, flags);
>> return;
>> @@ -2999,7 +2999,7 @@ trident_ac97_get(struct ac97_codec *codec, u8 reg)
>> } while (count--);
>> spin_unlock_irqrestore(&card->lock, flags);
>>
>> - if (count == 0) {
>> + if (count == -1) {
>> printk(KERN_ERR "trident: AC97 CODEC read timed out.\n");
>> data = 0;
>> }
>
> You didn't test this: count is unsigned. Change the loop condition to
> be --count instead.
>
> Ray
Yep, you're right, here:
--
If count reaches zero, the loop ends, but the postfix decrement still subtracts:
testing for 'count == 0' will not work.
Signed-off-by: Roel Kluin <[email protected]>
---
diff --git a/sound/oss/trident.c b/sound/oss/trident.c
index 96adc47..6959ee1 100644
--- a/sound/oss/trident.c
+++ b/sound/oss/trident.c
@@ -2935,7 +2935,7 @@ trident_ac97_set(struct ac97_codec *codec, u8 reg, u16 val)
do {
if ((inw(TRID_REG(card, address)) & busy) == 0)
break;
- } while (count--);
+ } while (--count);
data |= (mask | (reg & AC97_REG_ADDR));
@@ -2996,7 +2996,7 @@ trident_ac97_get(struct ac97_codec *codec, u8 reg)
data = inl(TRID_REG(card, address));
if ((data & busy) == 0)
break;
- } while (count--);
+ } while (--count);
spin_unlock_irqrestore(&card->lock, flags);
if (count == 0) {
-
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