[SCSI] aic7xxx: pause sequencer before touching SBLKCTL

Some cards need to pause the sequencer before the SBLKCTL register is
touched.  This fixes a PCI related oops seen on powerpc macs with this
card caused by trying to ascertain the bus signalling before beginning
domain validation.

Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index 0b3c01ac4259..64c8b88a429f 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -2539,6 +2539,7 @@ static void ahc_linux_set_iu(struct scsi_target *starget, int iu)
 static void ahc_linux_get_signalling(struct Scsi_Host *shost)
 {
         struct ahc_softc *ahc = *(struct ahc_softc **)shost->hostdata;
+        unsigned long flags;
         u8 mode;
 
         if (!(ahc->features & AHC_ULTRA2)) {
@@ -2550,7 +2551,11 @@ static void ahc_linux_get_signalling(struct Scsi_Host *shost)
                 return;
         }
 
+        ahc_lock(ahc, &flags);
+        ahc_pause(ahc);
         mode = ahc_inb(ahc, SBLKCTL);
+        ahc_unpause(ahc);
+        ahc_unlock(ahc, &flags);
 
         if (mode & ENAB40)
                 spi_signalling(shost) = SPI_SIGNAL_LVD;