From: Michal Maloszewski <michal.maloszewski@intel.com>
Date: Fri, 22 Jul 2022 10:54:01 -0700
Subject: i40e: Fix interface init with MSI interrupts (no MSI-X)
Patch-mainline: v5.19
Git-commit: 5fcbb711024aac6d4db385623e6f2fdf019f7782
References: jsc#SLE-18378

Fix the inability to bring an interface up on a setup with
only MSI interrupts enabled (no MSI-X).
Solution is to add a default number of QPs = 1. This is enough,
since without MSI-X support driver enables only a basic feature set.

Fixes: bc6d33c8d93f ("i40e: Fix the number of queues available to be mapped for use")
Signed-off-by: Dawid Lukwinski <dawid.lukwinski@intel.com>
Signed-off-by: Michal Maloszewski <michal.maloszewski@intel.com>
Tested-by: Dave Switzer <david.switzer@intel.com>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@intel.com>
Link: https://lore.kernel.org/r/20220722175401.112572-1-anthony.l.nguyen@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Acked-by: Thomas Bogendoerfer <tbogendoerfer@suse.de>
---
 drivers/net/ethernet/intel/i40e/i40e_main.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/net/ethernet/intel/i40e/i40e_main.c
+++ b/drivers/net/ethernet/intel/i40e/i40e_main.c
@@ -1908,11 +1908,15 @@ static void i40e_vsi_setup_queue_map(str
 		 * non-zero req_queue_pairs says that user requested a new
 		 * queue count via ethtool's set_channels, so use this
 		 * value for queues distribution across traffic classes
+		 * We need at least one queue pair for the interface
+		 * to be usable as we see in else statement.
 		 */
 		if (vsi->req_queue_pairs > 0)
 			vsi->num_queue_pairs = vsi->req_queue_pairs;
 		else if (pf->flags & I40E_FLAG_MSIX_ENABLED)
 			vsi->num_queue_pairs = pf->num_lan_msix;
+		else
+			vsi->num_queue_pairs = 1;
 	}
 
 	/* Number of queues per enabled TC */