[PATCH 3/6] wifi: mt76: mt792x: stop USB register access after bus hang
Sean Wang
sean.wang at kernel.org
Sat Jun 13 15:41:28 PDT 2026
From: Sean Wang <sean.wang at mediatek.com>
Mark the mt792x USB bus hung on the first control timeout and switch
register access to no-op bus ops. Each failed vendor request may spend
up to MT_VEND_REQ_MAX_RETRY * MT_VEND_REQ_TOUT_MS, about 3 seconds, and
teardown/reset paths can keep issuing such requests after the device has
stopped responding.
Also skip the USB WFSYS reset path after bus_hung is set, since it uses
UHW vendor requests as well.
mt7925u 1-2:1.3: vendor request req:63 off:0018 failed:-110
mt7925u 1-2:1.3: vendor request req:63 off:0018 failed:-110
mt7925u 1-2:1.3: vendor request req:63 off:0018 failed:-110
mt7925u 1-2:1.3: vendor request req:63 off:0018 failed:-110
mt7925u 1-2:1.3: vendor request req:63 off:0018 failed:-110
Avoid repeating those register reads after the bus is known to be hung by
switching register access to no-op handlers.
Fixes: 0d2afe09fad5 ("mt76: mt7921: add mt7921u driver")
Fixes: c948b5da6bbe ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 chips")
Signed-off-by: Sean Wang <sean.wang at mediatek.com>
---
drivers/net/wireless/mediatek/mt76/mt76.h | 1 +
.../net/wireless/mediatek/mt76/mt792x_usb.c | 79 ++++++++++++++++---
drivers/net/wireless/mediatek/mt76/usb.c | 11 +++
3 files changed, 82 insertions(+), 9 deletions(-)
diff --git a/drivers/net/wireless/mediatek/mt76/mt76.h b/drivers/net/wireless/mediatek/mt76/mt76.h
index 07955555f84d..122e77a5f2f4 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76.h
+++ b/drivers/net/wireless/mediatek/mt76/mt76.h
@@ -672,6 +672,7 @@ struct mt76_usb {
u8 out_ep[__MT_EP_OUT_MAX];
u8 in_ep[__MT_EP_IN_MAX];
+ void (*ctrl_timeout)(struct mt76_dev *dev, int err);
bool sg_en;
struct mt76u_mcu {
diff --git a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
index 910132e94956..d86b0918c2f8 100644
--- a/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
+++ b/drivers/net/wireless/mediatek/mt76/mt792x_usb.c
@@ -31,10 +31,75 @@ static void mt792xu_reset_work(struct work_struct *work)
atomic_set(&dev->usb_reset_pending, 0);
}
+static void mt792xu_queue_usb_reset(struct mt792x_dev *dev, int err)
+{
+ if (!atomic_xchg(&dev->usb_reset_pending, 1)) {
+ dev_warn(dev->mt76.dev,
+ "USB transport access failed (%d), queueing device reset\n",
+ err);
+
+ schedule_work(&dev->usb_reset_work);
+ }
+}
+
+static u32 mt792xu_bus_hung_rr(struct mt76_dev *mdev, u32 offset)
+{
+ return 0;
+}
+
+static void mt792xu_bus_hung_wr(struct mt76_dev *mdev, u32 offset, u32 val)
+{
+}
+
+static u32 mt792xu_bus_hung_rmw(struct mt76_dev *mdev, u32 offset,
+ u32 mask, u32 val)
+{
+ return 0;
+}
+
+static void mt792xu_bus_hung_write_copy(struct mt76_dev *mdev, u32 offset,
+ const void *data, int len)
+{
+}
+
+static void mt792xu_bus_hung_read_copy(struct mt76_dev *mdev, u32 offset,
+ void *data, int len)
+{
+ memset(data, 0, len);
+}
+
+static const struct mt76_bus_ops mt792xu_bus_hung_ops = {
+ .rr = mt792xu_bus_hung_rr,
+ .wr = mt792xu_bus_hung_wr,
+ .rmw = mt792xu_bus_hung_rmw,
+ .write_copy = mt792xu_bus_hung_write_copy,
+ .read_copy = mt792xu_bus_hung_read_copy,
+ .type = MT76_BUS_USB,
+};
+
+static void mt792xu_set_bus_hung(struct mt792x_dev *dev)
+{
+ atomic_set(&dev->mt76.bus_hung, true);
+
+ if (READ_ONCE(dev->mt76.bus) == &mt792xu_bus_hung_ops)
+ return;
+
+ WRITE_ONCE(dev->mt76.bus, &mt792xu_bus_hung_ops);
+}
+
+static void mt792xu_ctrl_timeout(struct mt76_dev *mdev, int err)
+{
+ struct mt792x_dev *dev = container_of(mdev, struct mt792x_dev, mt76);
+
+ mt792xu_set_bus_hung(dev);
+ mt792xu_queue_usb_reset(dev, err);
+}
+
void mt792xu_reset_work_init(struct mt792x_dev *dev)
{
INIT_WORK(&dev->usb_reset_work, mt792xu_reset_work);
atomic_set(&dev->usb_reset_pending, 0);
+ dev->mt76.usb.ctrl_timeout = mt792xu_ctrl_timeout;
}
EXPORT_SYMBOL_GPL(mt792xu_reset_work_init);
@@ -68,15 +133,8 @@ int mt792xu_reset_on_bus_error(struct mt792x_dev *dev)
err = mt792xu_check_bus(dev);
if (err) {
- atomic_set(&dev->mt76.bus_hung, true);
-
- if (!atomic_xchg(&dev->usb_reset_pending, 1)) {
- dev_warn(dev->mt76.dev,
- "USB transport access failed (%d), queueing device reset\n",
- err);
-
- schedule_work(&dev->usb_reset_work);
- }
+ mt792xu_set_bus_hung(dev);
+ mt792xu_queue_usb_reset(dev, err);
return err;
}
@@ -344,6 +402,9 @@ int mt792xu_wfsys_reset(struct mt792x_dev *dev)
u32 val;
int i;
+ if (atomic_read(&dev->mt76.bus_hung))
+ return -EIO;
+
mt792xu_epctl_rst_opt(dev, false);
val = mt792xu_uhw_rr(&dev->mt76, desc->rst_reg);
diff --git a/drivers/net/wireless/mediatek/mt76/usb.c b/drivers/net/wireless/mediatek/mt76/usb.c
index 77a8e35b1f86..ce68e1d0c786 100644
--- a/drivers/net/wireless/mediatek/mt76/usb.c
+++ b/drivers/net/wireless/mediatek/mt76/usb.c
@@ -30,6 +30,8 @@ int __mt76u_vendor_request(struct mt76_dev *dev, u8 req, u8 req_type,
for (i = 0; i < MT_VEND_REQ_MAX_RETRY; i++) {
if (test_bit(MT76_REMOVED, &dev->phy.state))
return -EIO;
+ if (dev->usb.ctrl_timeout && atomic_read(&dev->bus_hung))
+ return -EIO;
ret = usb_control_msg(udev, pipe, req, req_type, val,
offset, buf, len, MT_VEND_REQ_TOUT_MS);
@@ -42,6 +44,15 @@ int __mt76u_vendor_request(struct mt76_dev *dev, u8 req, u8 req_type,
dev_err(dev->dev, "vendor request req:%02x off:%04x failed:%d\n",
req, offset, ret);
+
+ if (dev->usb.ctrl_timeout) {
+ atomic_set(&dev->bus_hung, true);
+ dev_err(dev->dev, "vendor request req:%02x off:%04x timed out, marking bus hung\n",
+ req, offset);
+ dev->usb.ctrl_timeout(dev, ret);
+ return ret;
+ }
+
return ret;
}
EXPORT_SYMBOL_GPL(__mt76u_vendor_request);
--
2.43.0
More information about the Linux-mediatek
mailing list