esp_scsi: correctly detect am53c974

The am53c974 returns the same ID as the FAS236, but implements
things slightly differently. So detect the am53c974 by checking
for ESP_CONFIG4 register.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>

1 files changed, 2 insertions, 0 deletions

diff --git a/drivers/scsi/am53c974.c b/drivers/scsi/am53c974.c
index a42e8db057a4..6e88e38bd2a4 100644
--- a/drivers/scsi/am53c974.c
+++ b/drivers/scsi/am53c974.c
@@ -368,6 +368,8 @@ static void dc390_check_eeprom(struct esp *esp)
         }
         esp->scsi_id = EEbuf[DC390_EE_ADAPT_SCSI_ID];
         esp->num_tags = 2 << EEbuf[DC390_EE_TAG_CMD_NUM];
+        if (EEbuf[DC390_EE_MODE2] & DC390_EE_MODE2_ACTIVE_NEGATION)
+                esp->config4 |= ESP_CONFIG4_RADE | ESP_CONFIG4_RAE;
 }
 
 static int pci_esp_probe_one(struct pci_dev *pdev,