[SCSI] aic7xxx: avoid checking SBLKCTL register for certain cards
For cards that don't support LVD, checking the SBLKCTL register to
determine the bus singalling doesn't work. So, check that the card
supports LVD first (AHC_ULTRA2) before checking the register.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index e5bb4d8..0b3c01a 100644
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -2539,15 +2539,23 @@
static void ahc_linux_get_signalling(struct Scsi_Host *shost)
{
struct ahc_softc *ahc = *(struct ahc_softc **)shost->hostdata;
- u8 mode = ahc_inb(ahc, SBLKCTL);
+ u8 mode;
- if (mode & ENAB40)
- spi_signalling(shost) = SPI_SIGNAL_LVD;
- else if (mode & ENAB20)
+ if (!(ahc->features & AHC_ULTRA2)) {
+ /* non-LVD chipset, may not have SBLKCTL reg */
spi_signalling(shost) =
ahc->features & AHC_HVD ?
SPI_SIGNAL_HVD :
SPI_SIGNAL_SE;
+ return;
+ }
+
+ mode = ahc_inb(ahc, SBLKCTL);
+
+ if (mode & ENAB40)
+ spi_signalling(shost) = SPI_SIGNAL_LVD;
+ else if (mode & ENAB20)
+ spi_signalling(shost) = SPI_SIGNAL_SE;
else
spi_signalling(shost) = SPI_SIGNAL_UNKNOWN;
}