[PATCH] SCSI: aic7xxx: avoid checking SBLKCTL register for certain cards

[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>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Chris Wright <chrisw@sous-sol.org>

diff --git a/drivers/scsi/aic7xxx/aic7xxx_osm.c b/drivers/scsi/aic7xxx/aic7xxx_osm.c
index aa4be8a31415e1b7006ad1f22df8ce42e89cda73..34c9ca5e6d0518a34ab161ca08e9d697e3ed1f62 100644 (file)
--- a/drivers/scsi/aic7xxx/aic7xxx_osm.c
+++ b/drivers/scsi/aic7xxx/aic7xxx_osm.c
@@ -2539,15 +2539,23 @@ 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;
-       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;
 }