tableau-parm sometimes fails to open devices.

[pix]

It seems that r/w opening is required for tableau-parm to work sometimes since scsi_pt_open_device. Since I'm not sure about the reason behind opening it this way, I
only open it r/w if it fails first.

---
 src/tableau-parm.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/src/tableau-parm.c b/src/tableau-parm.c
index cbc5b77..e07e967 100644
--- a/src/tableau-parm.c
+++ b/src/tableau-parm.c
@@ -477,9 +477,14 @@ int main(int argc, char** argv)
    */
   sg_fd = scsi_pt_open_device(dev_file, 0 /* rw */, 0);
   if (sg_fd < 0) {
-    fprintf(stderr, "ERROR: scsi_pt_open_device failed on '%s' with: %s\n",
+    fprintf(stderr, "WARN: scsi_pt_open_device (ro) failed on '%s' with: %s\n",
 	    dev_file, strerror(-sg_fd));
-    return 1;
+    sg_fd = scsi_pt_open_device(dev_file, 1 /* rw */, 0);
+    if (sg_fd < 0) {
+      fprintf(stderr, "ERROR: scsi_pt_open_device failed on '%s' with: %s\n",
+          dev_file, strerror(-sg_fd));
+      return 1;
+    }
   }
 
   cmd_ret = sendCommand(sg_fd, tableau_query_cmd, 6, 
-- 
2.10.2

Hope it helps.