IB/ipath: Fix check for no interrupts to reliably fallback to INTx

Newer HCAs support MSI interrupts and also INTx interrupts.  Fix the
code so that INTx can be reliably enabled if MSI interrupts are not
working.

Signed-off-by: Dave Olson <dave.olson@qlogic.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 36 insertions, 0 deletions

diff --git a/drivers/infiniband/hw/ipath/ipath_init_chip.c b/drivers/infiniband/hw/ipath/ipath_init_chip.c
index 1adafa97e08..0db19c1b45c 100644
--- a/drivers/infiniband/hw/ipath/ipath_init_chip.c
+++ b/drivers/infiniband/hw/ipath/ipath_init_chip.c
@@ -665,6 +665,28 @@ done:
 	return ret;
 }
 
+static void verify_interrupt(unsigned long opaque)
+{
+	struct ipath_devdata *dd = (struct ipath_devdata *) opaque;
+
+	if (!dd)
+		return; /* being torn down */
+
+	/*
+	 * If we don't have any interrupts, let the user know and
+	 * don't bother checking again.
+	 */
+	if (dd->ipath_int_counter == 0) {
+		if (!dd->ipath_f_intr_fallback(dd))
+			dev_err(&dd->pcidev->dev, "No interrupts detected, "
+				"not usable.\n");
+		else /* re-arm the timer to see if fallback works */
+			mod_timer(&dd->ipath_intrchk_timer, jiffies + HZ/2);
+	} else
+		ipath_cdbg(VERBOSE, "%u interrupts at timer check\n",
+			dd->ipath_int_counter);
+}
+
 /**
  * ipath_init_chip - do the actual initialization sequence on the chip
  * @dd: the infinipath device
@@ -968,6 +990,20 @@ done:
 					 0ULL);
 			/* chip is usable; mark it as initialized */
 			*dd->ipath_statusp |= IPATH_STATUS_INITTED;
+
+			/*
+			 * setup to verify we get an interrupt, and fallback
+			 * to an alternate if necessary and possible
+			 */
+			if (!reinit) {
+				init_timer(&dd->ipath_intrchk_timer);
+				dd->ipath_intrchk_timer.function =
+					verify_interrupt;
+				dd->ipath_intrchk_timer.data =
+					(unsigned long) dd;
+			}
+			dd->ipath_intrchk_timer.expires = jiffies + HZ/2;
+			add_timer(&dd->ipath_intrchk_timer);
 		} else
 			ipath_dev_err(dd, "No interrupts enabled, couldn't "
 				      "setup interrupt address\n");