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authorArjan van de Ven <arjan@linux.intel.com>2008-04-08 17:41:55 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-04-08 18:25:53 -0700
commit4b47c971dc947cadecc20dc7681037e96ece520e (patch)
tree14afde1ea46a6b573ad1602e2ae440cb3f09ff1e
parent41e3355de052693c7a0cad74b845148d262edadf (diff)
es1968: fix sleep-while-holding-lock bug
snd_es1968_ac97_read() calls snd_es1968_ac97_wait() first outside a locked area, and later, while holding a lock. snd_es1968_ac97_wait() has a polling loop with a cond_resched() inside it.. which sleeps, so the second call is invalid. This patch adds a version of the wait function that just pure polls. While this is not very elegant in principle, it's very likely the easiest thing to do here, we already checked if the chip was ready (while yielding) just before, so it is very unlikely to take a long time here. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Cc: Jaroslav Kysela <perex@suse.cz> Cc: Takashi Iwai <tiwai@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--sound/pci/es1968.c14
1 files changed, 13 insertions, 1 deletions
diff --git a/sound/pci/es1968.c b/sound/pci/es1968.c
index 25ccfce4575..7d911a18c08 100644
--- a/sound/pci/es1968.c
+++ b/sound/pci/es1968.c
@@ -617,6 +617,18 @@ static int snd_es1968_ac97_wait(struct es1968 *chip)
return 1; /* timeout */
}
+static int snd_es1968_ac97_wait_poll(struct es1968 *chip)
+{
+ int timeout = 100000;
+
+ while (timeout-- > 0) {
+ if (!(inb(chip->io_port + ESM_AC97_INDEX) & 1))
+ return 0;
+ }
+ snd_printd("es1968: ac97 timeout\n");
+ return 1; /* timeout */
+}
+
static void snd_es1968_ac97_write(struct snd_ac97 *ac97, unsigned short reg, unsigned short val)
{
struct es1968 *chip = ac97->private_data;
@@ -645,7 +657,7 @@ static unsigned short snd_es1968_ac97_read(struct snd_ac97 *ac97, unsigned short
outb(reg | 0x80, chip->io_port + ESM_AC97_INDEX);
/*msleep(1);*/
- if (! snd_es1968_ac97_wait(chip)) {
+ if (!snd_es1968_ac97_wait_poll(chip)) {
data = inw(chip->io_port + ESM_AC97_DATA);
/*msleep(1);*/
}