Repeat by:
Put an audio CD in the ATAPI drive.
Invoke the program
#include <fcntl.h>
main(){
int i = open("/dev/cdrom", O_RDONLY);
if (i < 0)
perror("/dev/cdrom");
}
This will yield the output
/dev/cdrom: Wrong medium type
and now the drive door is locked, so that one
cannot replace the CD by the right one.
Explanation:
At various points the driver does a check media change,
which calls cdrom_check_status, which does a TEST_UNIT_READY.
However, the routine cdrom_queue_packet_command will always
lock the door unless called with one of a few commands,
and TEST_UNIT_READY is not one of those. So, each
cdrom_check_status, and each check media change will
lock the door. (Even after an eject the tray is withdrawn
and the door is closed again.)
This behaviour is avoided by making TEST_UNIT_READY one
of the exceptions in cdrom_queue_packet_command.
Patch:
--- /g1/linux/linux-2.3.14/linux/drivers/block/ide-cd.c Mon Aug 9 21:34:22 1999
+++ ide-cd.c Thu Aug 26 02:26:10 1999
@@ -1392,8 +1392,10 @@
and we think that the door is presently, lock it again.
(The door was probably unlocked via an explicit
CDROMEJECT ioctl.) */
- if (CDROM_STATE_FLAGS (drive)->door_locked == 0 && drive->usage &&
- (pc->c[0] != REQUEST_SENSE &&
+ if (CDROM_STATE_FLAGS (drive)->door_locked == 0 &&
+ drive->usage &&
+ (pc->c[0] != TEST_UNIT_READY &&
+ pc->c[0] != REQUEST_SENSE &&
pc->c[0] != ALLOW_MEDIUM_REMOVAL &&
pc->c[0] != START_STOP &&
pc->c[0] != MODE_SENSE_10 &&
-
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