[PATCH 1/2] cdrom: respect device capabilities during opening action

[PATCH 1/2] cdrom: respect device capabilities during opening action

[Diego Elio Pettenò]

Reading the TOC only works if the device can play audio, otherwise
these commands fail (and possibly bring the device to an unhealthy
state.)

Similarly, cdrom_mmc3_profile() should only be called if the device
supports generic packet commands.

To: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.com>
---
 drivers/cdrom/cdrom.c | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/cdrom/cdrom.c b/drivers/cdrom/cdrom.c
index ac42ae4651ce..eebdcbef0578 100644
--- a/drivers/cdrom/cdrom.c
+++ b/drivers/cdrom/cdrom.c
@@ -996,6 +996,12 @@ static void cdrom_count_tracks(struct cdrom_device_info *cdi, tracktype *tracks)
 	tracks->xa = 0;
 	tracks->error = 0;
 	cd_dbg(CD_COUNT_TRACKS, "entering cdrom_count_tracks\n");
+
+	if (!CDROM_CAN(CDC_PLAY_AUDIO)) {
+		tracks->error = CDS_NO_INFO;
+		return;
+	}
+
 	/* Grab the TOC header so we can see how many tracks there are */
 	ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCHDR, &header);
 	if (ret) {
@@ -1162,7 +1168,8 @@ int cdrom_open(struct cdrom_device_info *cdi, struct block_device *bdev,
 		ret = open_for_data(cdi);
 		if (ret)
 			goto err;
-		cdrom_mmc3_profile(cdi);
+		if (CDROM_CAN(CDC_GENERIC_PACKET))
+			cdrom_mmc3_profile(cdi);
 		if (mode & FMODE_WRITE) {
 			ret = -EROFS;
 			if (cdrom_open_write(cdi))
@@ -2882,6 +2889,9 @@ int cdrom_get_last_written(struct cdrom_device_info *cdi, long *last_written)
 	   it doesn't give enough information or fails. then we return
 	   the toc contents. */
 use_toc:
+	if (!CDROM_CAN(CDC_PLAY_AUDIO))
+		return -ENOSYS;
+
 	toc.cdte_format = CDROM_MSF;
 	toc.cdte_track = CDROM_LEADOUT;
 	if ((ret = cdi->ops->audio_ioctl(cdi, CDROMREADTOCENTRY, &toc)))
-- 
2.23.0

[PATCH 2/2] sr_vendor: support Beurer GL50 evo CD-on-a-chip devices.

[Diego Elio Pettenò]

The Beurer GL50 evo uses a Cygnal-manufactured CD-on-a-chip that only
accepts a subset of SCSI commands, and supports neither audio commands
nor generic packet commands.

Actually sending those commands bring the device to an unrecoverable
state that causes the device to hang and reset.

To: Jens Axboe <axboe@kernel.dk>
Cc: linux-kernel@vger.kernel.org
Cc: linux-scsi@vger.kernel.org
Signed-off-by: Diego Elio Pettenò <flameeyes@flameeyes.com>
---
 drivers/scsi/sr_vendor.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/drivers/scsi/sr_vendor.c b/drivers/scsi/sr_vendor.c
index e3b0ce25162b..17a56c87d383 100644
--- a/drivers/scsi/sr_vendor.c
+++ b/drivers/scsi/sr_vendor.c
@@ -61,6 +61,7 @@
 #define VENDOR_NEC             2
 #define VENDOR_TOSHIBA         3
 #define VENDOR_WRITER          4	/* pre-scsi3 writers */
+#define VENDOR_CYGNAL_85ED     5	/* CD-on-a-chip */
 
 #define VENDOR_TIMEOUT	30*HZ
 
@@ -99,6 +100,23 @@ void sr_vendor_init(Scsi_CD *cd)
 	} else if (!strncmp(vendor, "TOSHIBA", 7)) {
 		cd->vendor = VENDOR_TOSHIBA;
 
+	} else if (!strncmp(vendor, "Beurer", 6) &&
+		   !strncmp(model, "Gluco Memory", 12)) {
+		/* The Beurer GL50 evo uses a Cygnal-manufactured CD-on-a-chip
+		   that only accepts a subset of SCSI commands.  Most of the
+		   not-implemented commands are fine to fail, but a few,
+		   particularly around the MMC or Audio commands, will put the
+		   device into an unrecoverable state, so they need to be
+		   avoided at all costs.
+		*/
+		cd->vendor = VENDOR_CYGNAL_85ED;
+		cd->cdi.mask |= (
+			CDC_MULTI_SESSION |
+			CDC_CLOSE_TRAY | CDC_OPEN_TRAY |
+			CDC_LOCK |
+			CDC_GENERIC_PACKET |
+			CDC_PLAY_AUDIO
+			);
 	}
 #endif
 }
-- 
2.23.0

Re: [PATCH 1/2] cdrom: respect device capabilities during opening action

[Jens Axboe]

On 11/19/19 2:37 PM, Diego Elio Pettenò wrote:
> Reading the TOC only works if the device can play audio, otherwise
> these commands fail (and possibly bring the device to an unhealthy
> state.)
> 
> Similarly, cdrom_mmc3_profile() should only be called if the device
> supports generic packet commands.

Applied 1-2, thanks.

-- 
Jens Axboe