[PATCH 0/2] wifi: rtw89: fix RF calibration for USB transport

[PATCH 0/2] wifi: rtw89: fix RF calibration for USB transport

[Louis Kotze]

RF calibration on USB adapters (RTL8922AU) fails frequently because the
timeout values in rtw89_phy_rfk_report_wait() are designed for PCIe and
too tight for USB H2C/C2H round-trip latency.

Patch 1 applies a 4x timeout multiplier for USB devices, based on
measured calibration times from two independent testers across 2.4GHz,
5GHz, and 6GHz bands.

Patch 2 makes calibration timeouts non-fatal on USB, since the radio
continues to operate correctly despite occasional incomplete
calibrations. PCIe error handling is unchanged.

This is based on Ping-Ke's suggestion in the RTL8922AU support thread:
https://lore.kernel.org/linux-wireless/795a8567fdbe48babc5cf0f2b5e10c0a@realtek.com/

Louis Kotze (2):
  wifi: rtw89: phy: increase RF calibration timeouts for USB transport
  wifi: rtw89: phy: make RF calibration timeouts non-fatal on USB

 drivers/net/wireless/realtek/rtw89/phy.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

-- 
2.53.0

[PATCH 1/2] wifi: rtw89: phy: increase RF calibration timeouts for USB transport

[Louis Kotze]

USB transport adds significant latency to H2C/C2H round-trips used
by RF calibration. The existing timeout values were designed for PCIe
and are too tight for USB, causing "failed to wait RF DACK",
"failed to wait RF TSSI" and similar errors on USB adapters.

Apply a 4x timeout multiplier when the device uses USB transport.
The multiplier is applied in rtw89_phy_rfk_report_wait() so all
calibrations benefit without changing any call sites or PCIe
timeout values.

The 4x multiplier was chosen based on measured data from two
independent testers (RTL8922AU, 6GHz MLO and 2.4/5GHz):

  Calibration   PCIe timeout   Max measured (USB)   4x timeout
  PRE_NTFY           5ms              1ms              20ms
  DACK              58ms             72ms             232ms
  RX_DCK           128ms            374ms             512ms
  TSSI normal       20ms             24ms              80ms
  TSSI scan          6ms             14ms              24ms
  TXGAPK            54ms             18ms             216ms
  IQK               84ms             53ms             336ms
  DPK               34ms             30ms             136ms

Tested with RTL8922AU on 6GHz MLO (5GHz + 6GHz simultaneous):
25 connect/disconnect cycles with zero failures.

Signed-off-by: Louis Kotze <loukot@gmail.com>
---
 drivers/net/wireless/realtek/rtw89/phy.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw89/phy.c b/drivers/net/wireless/realtek/rtw89/phy.c
index e70d0e283..4d809df8b 100644
--- a/drivers/net/wireless/realtek/rtw89/phy.c
+++ b/drivers/net/wireless/realtek/rtw89/phy.c
@@ -3956,6 +3956,13 @@ int rtw89_phy_rfk_report_wait(struct rtw89_dev *rtwdev, const char *rfk_name,
 	struct rtw89_rfk_wait_info *wait = &rtwdev->rfk_wait;
 	unsigned long time_left;
 
+	/* USB transport adds latency to H2C/C2H round-trips, so RF
+	 * calibrations take longer than on PCIe. Apply a 4x multiplier
+	 * to avoid spurious timeouts.
+	 */
+	if (rtwdev->hci.type == RTW89_HCI_TYPE_USB)
+		ms *= 4;
+
 	/* Since we can't receive C2H event during SER, use a fixed delay. */
 	if (test_bit(RTW89_FLAG_SER_HANDLING, rtwdev->flags)) {
 		fsleep(1000 * ms / 2);
-- 
2.53.0

[PATCH 2/2] wifi: rtw89: phy: make RF calibration timeouts non-fatal on USB

[Louis Kotze]

On USB adapters, RF calibration timeouts can still occasionally occur
despite the increased timeout values, particularly under system load
or USB bus contention. However, the radio typically continues to
operate correctly despite an incomplete calibration — the timeout
does not indicate a hardware failure.

Make calibration timeouts and bad state returns non-fatal on USB by
logging at debug level and continuing, rather than returning
-ETIMEDOUT/-EFAULT which can cascade into a connection failure or
disconnect.

PCIe error handling is unchanged — timeouts remain fatal on PCIe
where they indicate a real problem.

Signed-off-by: Louis Kotze <loukot@gmail.com>
---
 drivers/net/wireless/realtek/rtw89/phy.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/drivers/net/wireless/realtek/rtw89/phy.c b/drivers/net/wireless/realtek/rtw89/phy.c
index 4d809df8b..a06bea88e 100644
--- a/drivers/net/wireless/realtek/rtw89/phy.c
+++ b/drivers/net/wireless/realtek/rtw89/phy.c
@@ -3972,9 +3972,21 @@ int rtw89_phy_rfk_report_wait(struct rtw89_dev *rtwdev, const char *rfk_name,
 	time_left = wait_for_completion_timeout(&wait->completion,
 						msecs_to_jiffies(ms));
 	if (time_left == 0) {
+		if (rtwdev->hci.type == RTW89_HCI_TYPE_USB) {
+			rtw89_debug(rtwdev, RTW89_DBG_RFK,
+				    "RF %s timeout (non-fatal on USB)\n",
+				    rfk_name);
+			goto out;
+		}
 		rtw89_warn(rtwdev, "failed to wait RF %s\n", rfk_name);
 		return -ETIMEDOUT;
 	} else if (wait->state != RTW89_RFK_STATE_OK) {
+		if (rtwdev->hci.type == RTW89_HCI_TYPE_USB) {
+			rtw89_debug(rtwdev, RTW89_DBG_RFK,
+				    "RF %s state %d (non-fatal on USB)\n",
+				    rfk_name, wait->state);
+			goto out;
+		}
 		rtw89_warn(rtwdev, "failed to do RF %s result from state %d\n",
 			   rfk_name, wait->state);
 		return -EFAULT;
-- 
2.53.0