[SCSI] sd: Avoid sending extended inquiry to legacy devices
Martin K. Petersen [Wed, 29 Jul 2009 18:06:53 +0000 (14:06 -0400)]
Some USB devices crash when we send them an inquiry with the EVPD bit
set, regardless of page requested (i.e. including page 0).

We only need the extended inquiry to gain access to VPD pages 0xB0 and
0xB1.  These appeared in SBC2 and SBC3 respectively, so we can restrict
sending the extended inquiry to devices reporting SPC3 or higher.

This fixes bugzilla.kernel.org #13657.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
[jejb: added comment]
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

drivers/scsi/sd.c

index 5616cd7..b7b9fec 100644 (file)
@@ -1840,6 +1840,18 @@ static void sd_read_block_characteristics(struct scsi_disk *sdkp)
        kfree(buffer);
 }
 
+static int sd_try_extended_inquiry(struct scsi_device *sdp)
+{
+       /*
+        * Although VPD inquiries can go to SCSI-2 type devices,
+        * some USB ones crash on receiving them, and the pages
+        * we currently ask for are for SPC-3 and beyond
+        */
+       if (sdp->scsi_level > SCSI_SPC_2)
+               return 1;
+       return 0;
+}
+
 /**
  *     sd_revalidate_disk - called the first time a new disk is seen,
  *     performs disk spin up, read_capacity, etc.
@@ -1877,8 +1889,12 @@ static int sd_revalidate_disk(struct gendisk *disk)
         */
        if (sdkp->media_present) {
                sd_read_capacity(sdkp, buffer);
-               sd_read_block_limits(sdkp);
-               sd_read_block_characteristics(sdkp);
+
+               if (sd_try_extended_inquiry(sdp)) {
+                       sd_read_block_limits(sdkp);
+                       sd_read_block_characteristics(sdkp);
+               }
+
                sd_read_write_protect_flag(sdkp, buffer);
                sd_read_cache_type(sdkp, buffer);
                sd_read_app_tag_own(sdkp, buffer);