e1000e: test for unusable MSI support

Some systems do not like 82571/2 use of 16-bit MSI messages and some
other systems claim to support MSI, but neither really works.  Setup a
test MSI handler to detect whether or not MSI is working properly, and
if not, fallback to legacy INTx interrupts.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/drivers/net/e1000e/e1000.h b/drivers/net/e1000e/e1000.h
index cf57050d99d8..ac4e506b4f88 100644
--- a/drivers/net/e1000e/e1000.h
+++ b/drivers/net/e1000e/e1000.h
@@ -326,6 +326,7 @@ struct e1000_info {
 #define FLAG_RX_CSUM_ENABLED              (1 << 28)
 #define FLAG_TSO_FORCE                    (1 << 29)
 #define FLAG_RX_RESTART_NOW               (1 << 30)
+#define FLAG_MSI_TEST_FAILED              (1 << 31)
 
 #define E1000_RX_DESC_PS(R, i)      \
         (&(((union e1000_rx_desc_packet_split *)((R).desc))[i]))