1 files changed, 17 insertions, 5 deletions

diff --git a/drivers/s390/cio/chsc.c b/drivers/s390/cio/chsc.c
index 9f0ea6cb6922..e3bf885f4a6c 100644
--- a/drivers/s390/cio/chsc.c
+++ b/drivers/s390/cio/chsc.c
@@ -541,18 +541,27 @@ static void chsc_process_sei_nt0(struct chsc_sei_nt0_area *sei_area)
 
 static void chsc_process_event_information(struct chsc_sei *sei, u64 ntsm)
 {
-        do {
+        static int ntsm_unsupported;
+
+        while (true) {
                 memset(sei, 0, sizeof(*sei));
                 sei->request.length = 0x0010;
                 sei->request.code = 0x000e;
-                sei->ntsm = ntsm;
+                if (!ntsm_unsupported)
+                        sei->ntsm = ntsm;
 
                 if (chsc(sei))
                         break;
 
                 if (sei->response.code != 0x0001) {
-                        CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x)\n",
-                                      sei->response.code);
+                        CIO_CRW_EVENT(2, "chsc: sei failed (rc=%04x, ntsm=%llx)\n",
+                                      sei->response.code, sei->ntsm);
+
+                        if (sei->response.code == 3 && sei->ntsm) {
+                                /* Fallback for old firmware. */
+                                ntsm_unsupported = 1;
+                                continue;
+                        }
                         break;
                 }
 
@@ -568,7 +577,10 @@ static void chsc_process_event_information(struct chsc_sei *sei, u64 ntsm)
                         CIO_CRW_EVENT(2, "chsc: unhandled nt: %d\n", sei->nt);
                         break;
                 }
-        } while (sei->u.nt0_area.flags & 0x80);
+
+                if (!(sei->u.nt0_area.flags & 0x80))
+                        break;
+        }
 }
 
 /*