Hi,
On 06/17/2012 05:26 PM, Alan Stern wrote:
On Fri, 15 Jun 2012, Alan Stern wrote:
On Fri, 15 Jun 2012, Hans de Goede wrote:
Hi,
On 06/15/2012 08:20 PM, Alan Stern wrote:
As we can see from recent bug reports, a lot of USB mass-storage
devices cannot handle READ CAPACITY(16) commands properly. They send
back garbage and are unusable as a result.
Should we go ahead and set a flag on all these devices, telling the sd
driver to try READ CAPACITY(10) first? That's a lot easier than adding
more and more entries to unusual_devs.h.
That certainly sound reasonable to me. Note that the 071b:3203 really
needs the US_FL_NO_READ_CAPACITY_16 flag though, as it wrongly reports
a capacity of -1 when there is no sd card in its slot, and in response
to that the kernel tries READ CAPACITY(16) and things go downhill
from there...
Yes, we need to be able to have both flags set for the same device.
For that card reader they would mean try READ CAPACITY(10) first, and
if it fails, don't try READ CAPACITY(16).
In other words, I'm suggesting we adopt this patch and get rid Hans's
new unusual_devs entry.
I understood as much already :)
Proposed patch (below) looks good:
Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Removing my new unusual_devs entry is also:
Acked-by: Hans de Goede <hdegoede@xxxxxxxxxx>
Regards,
Hans
Alan Stern
Index: usb-3.4/include/scsi/scsi_device.h
===================================================================
--- usb-3.4.orig/include/scsi/scsi_device.h
+++ usb-3.4/include/scsi/scsi_device.h
@@ -151,6 +151,7 @@ struct scsi_device {
SD_LAST_BUGGY_SECTORS */
unsigned no_read_disc_info:1; /* Avoid READ_DISC_INFO cmds */
unsigned no_read_capacity_16:1; /* Avoid READ_CAPACITY_16 cmds */
+ unsigned try_rc_10_first:1; /* Try READ_CAPACACITY_10 first */
unsigned is_visible:1; /* is the device visible in sysfs */
DECLARE_BITMAP(supported_events, SDEV_EVT_MAXBITS); /* supported events */
Index: usb-3.4/drivers/scsi/sd.c
===================================================================
--- usb-3.4.orig/drivers/scsi/sd.c
+++ usb-3.4/drivers/scsi/sd.c
@@ -1899,6 +1899,8 @@ static int sd_try_rc16_first(struct scsi
{
if (sdp->host->max_cmd_len< 16)
return 0;
+ if (sdp->try_rc_10_first)
+ return 0;
if (sdp->scsi_level> SCSI_SPC_2)
return 1;
if (scsi_device_protection(sdp))
Index: usb-3.4/drivers/usb/storage/scsiglue.c
===================================================================
--- usb-3.4.orig/drivers/usb/storage/scsiglue.c
+++ usb-3.4/drivers/usb/storage/scsiglue.c
@@ -202,6 +202,12 @@ static int slave_configure(struct scsi_d
if (us->fflags& US_FL_NO_READ_CAPACITY_16)
sdev->no_read_capacity_16 = 1;
+ /*
+ * Many devices do not respond properly to READ_CAPACITY_16.
+ * Tell the SCSI layer to try READ_CAPACITY_10 first.
+ */
+ sdev->try_rc_10_first = 1;
+
/* assume SPC3 or latter devices support sense size> 18 */
if (sdev->scsi_level> SCSI_SPC_2)
us->fflags |= US_FL_SANE_SENSE;
--
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