face
    is down; the new value is picked up by the next init.
    
    Unlike e1000, igc has no ASSERT_CTX_LOCK_HELD and no acquire_swflag
    path, so the defect is silent here rather than an assertion failure.
    
    While here also remove unnecessary igc_if_init uses:
    iflib_if_init_locked() already runs after IFDI_RESUME and
    IFDI_MEDIA_CHANGE, so the trailing *_if_init() only added an unstopped
    IFDI_INIT that the following iflib_stop() undoes.
    
    Differential Revision:  https://reviews.freebsd.org/D58629
    
    (cherry picked from commit 30ccf2f48c11e54fc0540510dcec7cd006a2c366)
---
 sys/dev/igc/if_igc.c | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)

diff --git a/sys/dev/igc/if_igc.c b/sys/dev/igc/if_igc.c
index fe278f2029f3..c49948f7c57e 100644
--- a/sys/dev/igc/if_igc.c
+++ b/sys/dev/igc/if_igc.c
@@ -807,8 +807,6 @@ igc_if_resume(if_ctx_t ctx)
 	 */
 	igc_disable_broken_l1_2(ctx);
 
-	igc_if_init(ctx);
-
 	return(0);
 }
 
@@ -1288,8 +1286,6 @@ igc_if_media_change(if_ctx_t ctx)
 		device_printf(sc->dev, "Unsupported media type\n");
 	}
 
-	igc_if_init(ctx);
-
 	return (0);
 }
 
@@ -3224,6 +3220,16 @@ igc_set_flowcntl(SYSCTL_HANDLER_ARGS)
 	return (error);
 }
 
+static void
+igc_sysctl_request_reinit(struct igc_softc *sc)
+{
+	if ((if_getflags(iflib_get_ifp(sc->ctx)) & IFF_UP) == 0)
+		return;
+
+	iflib_request_reset(sc->ctx);
+	iflib_admin_intr_deferred(sc->ctx);
+}
+
 /*
  * Manage DMA Coalesce:
  * Control values:
@@ -3269,7 +3275,7 @@ igc_sysctl_dmac(SYSCTL_HANDLER_ARGS)
 			return (EINVAL);
 	}
 	/* Reinit the interface */
-	igc_if_init(sc->ctx);
+	igc_sysctl_request_reinit(sc);
 	return (error);
 }
 
@@ -3290,7 +3296,7 @@ igc_sysctl_eee(SYSCTL_HANDLER_ARGS)
 		return (error);
 
 	sc->hw.dev_spec._i225.eee_disable = (value != 0);
-	igc_if_init(sc->ctx);
+	igc_sysctl_request_reinit(sc);
 
 	return (0);
 }