[S390] cio: Make isc handling more robust.

Introduce an ->isc field in the subchannel to store the desired
interruption subclass, since sch->schib.pmcw.isc may be overwritten
by the hardware on stsch() after machine checks.

Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 4 insertions, 5 deletions

diff --git a/drivers/s390/cio/cio.c b/drivers/s390/cio/cio.c
index 23ffcc4768a7..08a578161306 100644
--- a/drivers/s390/cio/cio.c
+++ b/drivers/s390/cio/cio.c
@@ -407,8 +407,7 @@ cio_modify (struct subchannel *sch)
 /*
  * Enable subchannel.
  */
-int cio_enable_subchannel(struct subchannel *sch, unsigned int isc,
-                          u32 intparm)
+int cio_enable_subchannel(struct subchannel *sch, u32 intparm)
 {
         char dbf_txt[15];
         int ccode;
@@ -426,7 +425,7 @@ int cio_enable_subchannel(struct subchannel *sch, unsigned int isc,
 
         for (retry = 5, ret = 0; retry > 0; retry--) {
                 sch->schib.pmcw.ena = 1;
-                sch->schib.pmcw.isc = isc;
+                sch->schib.pmcw.isc = sch->isc;
                 sch->schib.pmcw.intparm = intparm;
                 ret = cio_modify(sch);
                 if (ret == -ENODEV)
@@ -600,6 +599,7 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
         else
                 sch->opm = chp_get_sch_opm(sch);
         sch->lpm = sch->schib.pmcw.pam & sch->opm;
+        sch->isc = 3;
 
         CIO_DEBUG(KERN_INFO, 0,
                   "Detected device %04x on subchannel 0.%x.%04X"
@@ -610,13 +610,11 @@ cio_validate_subchannel (struct subchannel *sch, struct subchannel_id schid)
 
         /*
          * We now have to initially ...
-         *  ... set "interruption subclass"
          *  ... enable "concurrent sense"
          *  ... enable "multipath mode" if more than one
          *        CHPID is available. This is done regardless
          *        whether multiple paths are available for us.
          */
-        sch->schib.pmcw.isc = 3;        /* could be smth. else */
         sch->schib.pmcw.csense = 1;     /* concurrent sense */
         sch->schib.pmcw.ena = 0;
         if ((sch->lpm & (sch->lpm - 1)) != 0)
@@ -812,6 +810,7 @@ cio_probe_console(void)
          * enable console I/O-interrupt subclass 7
          */
         ctl_set_bit(6, 24);
+        console_subchannel.isc = 7;
         console_subchannel.schib.pmcw.isc = 7;
         console_subchannel.schib.pmcw.intparm =
                 (u32)(addr_t)&console_subchannel;