linux-kernel - [PATCH] ali5451: fix timeout handling in snd_ali_{codecs,timer}

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Date:	Wed, 19 Aug 2009 22:09:50 +0200
From:	Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
To:	Takashi Iwai <tiwai@...e.de>
Cc:	Jack Byer <ojbyer@....net>, alsa-devel@...a-project.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] ali5451: fix timeout handling in snd_ali_{codecs,timer}_ready()

From: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
Subject: [PATCH] ali5451: fix timeout handling in snd_ali_{codecs,timer}_ready()

Modify loops in such way that the register value is checked also after
the timeout condition, just in case the heavy interrupt load etc. caused
the thread to sleep for the time period exceeding the timeout value.

While at it remove an extra ALI_STIMER read from snd_ali_stimer_ready().

Reported-by: Jack Byer <ojbyer@....net>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@...il.com>
---
 sound/pci/ali5451/ali5451.c |   11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

Index: b/sound/pci/ali5451/ali5451.c
===================================================================
--- a/sound/pci/ali5451/ali5451.c
+++ b/sound/pci/ali5451/ali5451.c
@@ -314,8 +314,11 @@ static int snd_ali_codec_ready(struct sn
 		res = snd_ali_5451_peek(codec,port);
 		if (!(res & 0x8000))
 			return 0;
+		if (!time_after_eq(end_time, jiffies))
+			break;
 		schedule_timeout_uninterruptible(1);
-	} while (time_after_eq(end_time, jiffies));
+	} while (1);
+
 	snd_ali_5451_poke(codec, port, res & ~0x8000);
 	snd_printdd("ali_codec_ready: codec is not ready.\n ");
 	return -EIO;
@@ -327,15 +330,17 @@ static int snd_ali_stimer_ready(struct s
 	unsigned long dwChk1,dwChk2;
 	
 	dwChk1 = snd_ali_5451_peek(codec, ALI_STIMER);
-	dwChk2 = snd_ali_5451_peek(codec, ALI_STIMER);
 
 	end_time = jiffies + msecs_to_jiffies(250);
 	do {
 		dwChk2 = snd_ali_5451_peek(codec, ALI_STIMER);
 		if (dwChk2 != dwChk1)
 			return 0;
+		if (!time_after_eq(end_time, jiffies))
+			break;
 		schedule_timeout_uninterruptible(1);
-	} while (time_after_eq(end_time, jiffies));
+	} while (1);
+
 	snd_printk(KERN_ERR "ali_stimer_read: stimer is not ready.\n");
 	return -EIO;
 }
--
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