[Intel-wired-lan] [next PATCH S28 09/15] i40e: Do not disable queues in the Legacy/MSI Interrupt handler

Joshua Hay joshua.a.hay at intel.com
Fri Jan 15 22:33:16 UTC 2016


From: Anjali Singhai Jain <anjali.singhai at intel.com>

The queues should never be enabled/disabled in the interrupt handler,
ICR0 interrupt enable should be the only thing that needs to be
dynamically changed in the handler.

This patch fixes that. Without this patch X722 platforms were
seeing weird ping timings when in Legacy mode since it takes
a whole lot of time for the HW/FW to re-enable queues.

Signed-off-by: Anjali Singhai Jain <anjali.singhai at intel.com>
Change-ID: If065afc45d81c5a19d4a94a00cd5b8f61cefc40c
---
Testing Hints (Required if no HSD): Test with legacy mode
enabled.

 drivers/net/ethernet/intel/i40e/i40e_main.c | 16 ++++++----------
 drivers/net/ethernet/intel/i40e/i40e_txrx.c | 13 -------------
 2 files changed, 6 insertions(+), 23 deletions(-)

diff --git a/drivers/net/ethernet/intel/i40e/i40e_main.c b/drivers/net/ethernet/intel/i40e/i40e_main.c
index 90e37f4..5e7a7a1 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -3462,16 +3462,12 @@ static irqreturn_t i40e_intr(int irq, void *data)
 		struct i40e_vsi *vsi = pf->vsi[pf->lan_vsi];
 		struct i40e_q_vector *q_vector = vsi->q_vectors[0];
 
-		/* temporarily disable queue cause for NAPI processing */
-		u32 qval = rd32(hw, I40E_QINT_RQCTL(0));
-
-		qval &= ~I40E_QINT_RQCTL_CAUSE_ENA_MASK;
-		wr32(hw, I40E_QINT_RQCTL(0), qval);
-
-		qval = rd32(hw, I40E_QINT_TQCTL(0));
-		qval &= ~I40E_QINT_TQCTL_CAUSE_ENA_MASK;
-		wr32(hw, I40E_QINT_TQCTL(0), qval);
-
+		/* We do not have a way to disarm Queue causes while leaving
+		 * interrupt enabled for all other causes, ideally
+		 * interrupt should be disabled while we are in NAPI but
+		 * this is not a performance path and napi_schedule()
+		 * can deal with rescheduling.
+		 */
 		if (!test_bit(__I40E_DOWN, &pf->state))
 			napi_schedule_irqoff(&q_vector->napi);
 	}
diff --git a/drivers/net/ethernet/intel/i40e/i40e_txrx.c b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
index cd9bb7f..61e98f5 100644
--- a/drivers/net/ethernet/intel/i40e/i40e_txrx.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_txrx.c
@@ -2051,19 +2051,6 @@ tx_only:
 	if (vsi->back->flags & I40E_FLAG_MSIX_ENABLED) {
 		i40e_update_enable_itr(vsi, q_vector);
 	} else { /* Legacy mode */
-		struct i40e_hw *hw = &vsi->back->hw;
-		/* We re-enable the queue 0 cause, but
-		 * don't worry about dynamic_enable
-		 * because we left it on for the other
-		 * possible interrupts during napi
-		 */
-		u32 qval = rd32(hw, I40E_QINT_RQCTL(0)) |
-			   I40E_QINT_RQCTL_CAUSE_ENA_MASK;
-
-		wr32(hw, I40E_QINT_RQCTL(0), qval);
-		qval = rd32(hw, I40E_QINT_TQCTL(0)) |
-		       I40E_QINT_TQCTL_CAUSE_ENA_MASK;
-		wr32(hw, I40E_QINT_TQCTL(0), qval);
 		i40e_irq_dynamic_enable_icr0(vsi->back, false);
 	}
 	return 0;
-- 
2.1.0



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