[SCSI] aic79xx: SLOWCRC fix

This patch introduces the SLOWCRC handling for certain buggy chipsets.

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

1 files changed, 21 insertions, 0 deletions

diff --git a/drivers/scsi/aic7xxx/aic79xx_core.c b/drivers/scsi/aic7xxx/aic79xx_core.c
index dfd4cc93c05..6114b3e72ca 100644
--- a/drivers/scsi/aic7xxx/aic79xx_core.c
+++ b/drivers/scsi/aic7xxx/aic79xx_core.c
@@ -3332,6 +3332,15 @@ ahd_update_neg_table(struct ahd_softc *ahd, struct ahd_devinfo *devinfo,
                 con_opts |= WIDEXFER;
 
         /*
+         * Slow down our CRC interval to be
+         * compatible with packetized U320 devices
+         * that can't handle a CRC at full speed
+         */
+        if (ahd->features & AHD_AIC79XXB_SLOWCRC) {
+                con_opts |= ENSLOWCRC;
+        }
+
+        /*
          * During packetized transfers, the target will
          * give us the oportunity to send command packets
          * without us asserting attention.
@@ -6740,6 +6749,18 @@ ahd_chip_init(struct ahd_softc *ahd)
 
         ahd_loadseq(ahd);
         ahd_set_modes(ahd, AHD_MODE_SCSI, AHD_MODE_SCSI);
+
+        if (ahd->features & AHD_AIC79XXB_SLOWCRC) {
+                u_int negodat3 = ahd_inb(ahd, NEGCONOPTS);
+
+                negodat3 |= ENSLOWCRC;
+                ahd_outb(ahd, NEGCONOPTS, negodat3);
+                negodat3 = ahd_inb(ahd, NEGCONOPTS);
+                if (!(negodat3 & ENSLOWCRC))
+                        printf("aic79xx: failed to set the SLOWCRC bit\n");
+                else
+                        printf("aic79xx: SLOWCRC bit set\n");
+        }
 }
 
 /*