linux-kernel - Re: [PATCH] cdrom: longer timeout for "Read Track Info" command

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Message-ID: <20070102135052.GA2483@kernel.dk>
Date:	Tue, 2 Jan 2007 14:50:53 +0100
From:	Jens Axboe <jens.axboe@...cle.com>
To:	Alan <alan@...rguk.ukuu.org.uk>
Cc:	Jeremy Higdon <jeremy@....com>, linux-kernel@...r.kernel.org,
	linux-ide@...r.kernel.org, akpm@...l.org
Subject: Re: [PATCH] cdrom: longer timeout for "Read Track Info" command

On Tue, Jan 02 2007, Alan wrote:
> On Mon, 1 Jan 2007 18:36:24 -0800
> Jeremy Higdon <jeremy@....com> wrote:
> 
> > I have a DVD combo drive and a CD in which the
> > "READ TRACK INFORMATION" command (implemented in the
> > cdrom_get_track_info() function) takes about 7 seconds to run.
> > The current implementation of cdrom_get_track_info() uses the
> > default timeout of 5 seconds.  So here's a patch that increases
> > the timeout from 5 to 15 seconds.
> > 
> > The drive in question is a TSSTcorpCD/DVDW SN-S082D, and I have
> > a Silicon Image 680A adapter, in case that's of interest.
> > 
> > signed-off-by: <jeremy@....com>
> 
> Please test with a seven second timeout rather than fifteen which is way
> longer than anyone wants to wait. Seven is the magic value used by
> another major vendor so ought to be right for all hardware 8)

Yep, I suspect this patch is long overdue. Jeremy, is this enough to fix
it for you?

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index 66d028d..3105ddd 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -337,6 +337,12 @@ static const char *mrw_address_space[] = { "DMA", "GAA" };
 /* used in the audio ioctls */
 #define CHECKAUDIO if ((ret=check_for_audio_disc(cdi, cdo))) return ret
 
+/*
+ * Another popular OS uses 7 seconds as the hard timeout for default
+ * commands, so it is a good choice for us as well.
+ */
+#define CDROM_DEF_TIMEOUT	(7 * HZ)
+
 /* Not-exported routines. */
 static int open_for_data(struct cdrom_device_info * cdi);
 static int check_for_audio_disc(struct cdrom_device_info * cdi,
@@ -1528,7 +1534,7 @@ void init_cdrom_command(struct packet_command *cgc, void *buf, int len,
 	cgc->buffer = (char *) buf;
 	cgc->buflen = len;
 	cgc->data_direction = type;
-	cgc->timeout = 5*HZ;
+	cgc->timeout = CDROM_DEF_TIMEOUT;
 }
 
 /* DVD handling */

-- 
Jens Axboe

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