From: Prasanna S. Panchamukhi <ppanchamu...@riverbed.com>
Following logs where seen on Systems with multiple NICs & ports,
while using MSI interrupts as shown below:
Feb 16 15:09:32 (none) user.notice kernel: 0000:00:0d.0: lan0_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:32 (none) user.notice kernel: 0000:40:0d.0: wan0_1: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:32 (none) user.notice kernel: 0000:40:0d.0: lan0_1: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:32 (none) user.warn kernel: 0000:40:0e.0: wan4_0: MSI interrupt
test failed, using legacy interrupt.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Feb 16 15:09:32 (none) user.notice kernel: 0000:00:0e.0: wan1_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:33 (none) user.notice kernel: 0000:00:0e.0: lan1_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:33 (none) user.notice kernel: 0000:00:0f.0: wan2_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:33 (none) user.notice kernel: 0000:00:0f.0: lan2_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:33 (none) user.notice kernel: 0000:40:0a.0: wan3_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:33 (none) user.notice kernel: 0000:40:0a.0: lan3_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:34 (none) user.notice kernel: 0000:40:0e.0: lan4_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:34 (none) user.notice kernel: 0000:40:0f.0: wan5_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
Feb 16 15:09:34 (none) user.notice kernel: 0000:40:0f.0: lan5_0: NIC Link is Up
1000 Mbps Full Duplex, Flow Control: RX/TX
This patch changes the IRQ tests to use polling loops starting with a
delay of 1 tick and doubling that if necessary up to a maximum total
delay of approximately 1 second.
Signed-off-by: Prasanna S. Panchamukhi <ppanchamu...@riverbed.com>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 27 +++++++++++++++++++++++----
1 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c
b/drivers/net/ethernet/intel/e1000e/netdev.c
index 19ab215..8ff0fff 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -98,6 +98,16 @@ struct e1000_reg_info {
#define E1000_TDFTS 0x03428 /* Tx Data FIFO Tail Saved - RW */
#define E1000_TDFPC 0x03430 /* Tx Data FIFO Packet Count - RW */
+/* IRQ latency can be enormous because:
+ * - All IRQs may be disabled on a CPU for a *long* time by e.g. a
+ * slow serial console or an old IDE driver doing error recovery
+ * - The PREEMPT_RT patches mostly deal with this, but also allow a
+ * tasklet or normal task to be given higher priority than our IRQ
+ * threads
+ * Try to avoid blaming the hardware for this.
+ */
+#define IRQ_TIMEOUT HZ
+
static const struct e1000_reg_info e1000_reg_info_tbl[] = {
/* General Registers */
@@ -3767,6 +3777,7 @@ static int e1000_test_msi_interrupt(struct e1000_adapter
*adapter)
{
struct net_device *netdev = adapter->netdev;
struct e1000_hw *hw = &adapter->hw;
+ unsigned long timeout, wait;
int err;
/* poll_enable hasn't been called yet, so don't need disable */
@@ -3799,12 +3810,20 @@ static int e1000_test_msi_interrupt(struct
e1000_adapter *adapter)
/* fire an unusual interrupt on the test handler */
ew32(ICS, E1000_ICS_RXSEQ);
e1e_flush();
- msleep(50);
-
+ timeout = jiffies + IRQ_TIMEOUT;
+ wait = 1;
+ e_dbg("Waiting for MSI interrupt!\n");
+ do {
+ schedule_timeout_uninterruptible(wait);
+ rmb();
+ if (!(adapter->flags & FLAG_MSI_TEST_FAILED))
+ goto success;
+ wait *= 2;
+ } while (time_before(jiffies, timeout));
+
+success:
e1000_irq_disable(adapter);
- rmb();
-
if (adapter->flags & FLAG_MSI_TEST_FAILED) {
adapter->int_mode = E1000E_INT_MODE_LEGACY;
e_info("MSI interrupt test failed, using legacy interrupt.\n");
--
1.7.0.4
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