hpsa: do not attempt to read from a write-only register

commit fec62c368b9c8b05d5124ca6c3b8336b537f26f3 upstream.

Most smartarrays tolerate it, but a few new ones don't.
Without this change some newer Smart Arrays will lock up
and i/o will grind to a halt.

Signed-off-by: Stephen M. Cameron <scameron@beardog.cce.hp.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/scsi/hpsa.h b/drivers/scsi/hpsa.h
index 6d8dcd4..7f53cea 100644 (file)
--- a/drivers/scsi/hpsa.h
+++ b/drivers/scsi/hpsa.h
@@ -214,7 +214,7 @@ static void SA5_submit_command(struct ctlr_info *h,
        dev_dbg(&h->pdev->dev, "Sending %x, tag = %x\n", c->busaddr,
                c->Header.Tag.lower);
        writel(c->busaddr, h->vaddr + SA5_REQUEST_PORT_OFFSET);
-       (void) readl(h->vaddr + SA5_REQUEST_PORT_OFFSET);
+       (void) readl(h->vaddr + SA5_SCRATCHPAD_OFFSET);
        h->commands_outstanding++;
        if (h->commands_outstanding > h->max_outstanding)
                h->max_outstanding = h->commands_outstanding;