diff --git a/share/man/man4/alc.4 b/share/man/man4/alc.4
--- a/share/man/man4/alc.4
+++ b/share/man/man4/alc.4
@@ -22,7 +22,7 @@
 .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 .\" SUCH DAMAGE.
 .\"
-.Dd August 22, 2016
+.Dd May 28, 2025
 .Dt ALC 4
 .Os
 .Sh NAME
@@ -136,11 +136,9 @@
 The default value is 0.
 .It Va hw.alc.msix_disable
 This tunable disables MSI-X support on the Ethernet hardware.
-The default value is 2, which means to enable or disable MSI-X based on the
-card type; for "Killer" cards (E2x00) MSI-X will be disabled, while on other
-cards it will be enabled.
-Set this to 0 to force MSI-X to be enabled, or 1 to force it to be disabled
-regardless of card type.
+The default value is 1, since many AR81xx cards do not work with
+MSI-x enabled.
+Set this to 0 to force MSI-X to be enabled.
 .El
 .Sh SYSCTL VARIABLES
 The following variables are available as both
diff --git a/sys/dev/alc/if_alc.c b/sys/dev/alc/if_alc.c
--- a/sys/dev/alc/if_alc.c
+++ b/sys/dev/alc/if_alc.c
@@ -94,11 +94,9 @@
 TUNABLE_INT("hw.alc.msi_disable", &msi_disable);
 
 /*
- * The default value of msix_disable is 2, which means to decide whether to
- * enable MSI-X in alc_attach() depending on the card type.  The operator can
- * set this to 0 or 1 to override the default.
+ * Many AR81xx cards do not handle MSI-X properly, so disable it by default.
  */
-static int msix_disable = 2;
+static int msix_disable = 1;
 TUNABLE_INT("hw.alc.msix_disable", &msix_disable);
 
 /*
@@ -1416,14 +1414,6 @@
 	case DEVICEID_ATHEROS_E2400:
 	case DEVICEID_ATHEROS_E2500:
 		sc->alc_flags |= ALC_FLAG_E2X00;
-
-		/*
-		 * Disable MSI-X by default on Killer devices, since this is
-		 * reported by several users to not work well.
-		 */
-		if (msix_disable == 2)
-			msix_disable = 1;
-
 		/* FALLTHROUGH */
 	case DEVICEID_ATHEROS_AR8161:
 		if (pci_get_subvendor(dev) == VENDORID_ATHEROS &&
@@ -1454,13 +1444,6 @@
 		break;
 	}
 
-	/*
-	 * The default value of msix_disable is 2, which means auto-detect.  If
-	 * we didn't auto-detect it, default to enabling it.
-	 */
-	if (msix_disable == 2)
-		msix_disable = 0;
-
 	sc->alc_flags |= ALC_FLAG_JUMBO;
 
 	/*