cdrom: set default timeout to 7 seconds

It's a known fact that Windows times out commands after 7 seconds, so
drives generally try and respond if they can before that happens.  We
default to 5 seconds, which sometimes is a bit too short.

Jeremy Higdon reported here:

    http://lkml.org/lkml/2007/1/1/145

that his drive takes longer than 5 seconds for a "read track
information" command, later confirming that it is about 6.7 seconds.

So just do the sane thing and change the default command timeout to 7
seconds to avoid other surprises.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Adrian Bunk <bunk@stusta.de>

drivers/cdrom/cdrom.c

@@ -338,6 +338,12 @@ 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 */