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From:   Ben Hutchings <ben@decadent.org.uk>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
CC:     akpm@linux-foundation.org, Denis Kirjanov <kda@linux-powerpc.org>,
        "Takashi Iwai" <tiwai@suse.de>
Date:   Fri, 24 Apr 2020 00:05:55 +0100
Message-ID: <lsq.1587683028.294829156@decadent.org.uk>
Subject: [PATCH 3.16 128/245] ALSA: hda/ca0132 - Avoid endless loop
In-Reply-To: <lsq.1587683027.831233700@decadent.org.uk>
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3.16.83-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Takashi Iwai <tiwai@suse.de>

commit cb04fc3b6b076f67d228a0b7d096c69ad486c09c upstream.

Introduce a timeout to dspio_clear_response_queue() so that it won't
be caught in an endless loop even if the hardware doesn't respond
properly.

Fixes: a73d511c4867 ("ALSA: hda/ca0132: Add unsol handler for DSP and jack detection")
Link: https://lore.kernel.org/r/20191213085111.22855-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
 sound/pci/hda/patch_ca0132.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/sound/pci/hda/patch_ca0132.c
+++ b/sound/pci/hda/patch_ca0132.c
@@ -1271,13 +1271,14 @@ struct scp_msg {
 
 static void dspio_clear_response_queue(struct hda_codec *codec)
 {
+	unsigned long timeout = jiffies + msecs_to_jiffies(1000);
 	unsigned int dummy = 0;
-	int status = -1;
+	int status;
 
 	/* clear all from the response queue */
 	do {
 		status = dspio_read(codec, &dummy);
-	} while (status == 0);
+	} while (status == 0 && time_before(jiffies, timeout));
 }
 
 static int dspio_get_response_data(struct hda_codec *codec)