From 94ccf2d4ef1a67bf751d6c8fbd98a948b659dcca Mon Sep 17 00:00:00 2001
From: deck <deck@steammachine>
Date: Fri, 7 Aug 2026 07:24:56 +0100
Subject: [PATCH] fix: restore radio power mode and calibration on resume

xone_mt76_resume_radio() only cleared wake-on-wireless, switched
channel, re-enabled beacons and set MAC RX/TX. It never returned the
MCU to MT_RADIO_ON and never redid the RXDCOC/RC/temperature
calibrations that init_radio() performs via calibrate_radio().

The MAC layer survives a system suspend, so after resume the dongle
still beacons and a controller still associates - but the uncalibrated
RF path cannot sustain the link. It collapses a few seconds later and
the controller reassociates roughly every 10 seconds indefinitely.
Only a full USB re-enumeration (which reruns init_radio) recovered it.

Mirror init_radio() in the resume path: set_power_mode(MT_RADIO_ON),
calibrate_radio(), then the existing channel switch plus the mandatory
post-channel-change delay.

This affects the .resume path only. The .reset_resume path already
reinitialises via xone_dongle_init().
---
 transport/mt76.c | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/transport/mt76.c b/transport/mt76.c
index ecdbde4..c90ed75 100644
--- a/transport/mt76.c
+++ b/transport/mt76.c
@@ -1075,10 +1075,33 @@ int xone_mt76_resume_radio(struct xone_mt76 *mt)
 	if (err)
 		return err;
 
+	/*
+	 * The RF front end does not survive a system suspend: the MCU leaves
+	 * MT_RADIO_ON and the RXDCOC/RC/temperature calibrations applied by
+	 * init_radio() are lost. The MAC layer does survive, so the dongle
+	 * still beacons and a controller still associates - but an
+	 * uncalibrated RF path cannot sustain the link, so it collapses a few
+	 * seconds later and the controller reassociates every ~10s forever.
+	 *
+	 * Restore the radio power mode and redo the calibration, mirroring
+	 * init_radio(). calibrate_radio() leaves MT_MAC_SYS_CTRL with RX and
+	 * TX enabled; it is re-applied below after the channel switch.
+	 */
+	err = xone_mt76_set_power_mode(mt, MT_RADIO_ON);
+	if (err)
+		return err;
+
+	err = xone_mt76_calibrate_radio(mt);
+	if (err)
+		return err;
+
 	err = xone_mt76_switch_channel(mt, mt->channel);
 	if (err)
 		return err;
 
+	/* mandatory delay after channel change */
+	msleep(1000);
+
 	err = xone_mt76_set_pairing(mt, false);
 	if (err)
 		return err;