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Message-ID: <20250804142258.1577-1-selvarasu.g@samsung.com>
Date: Mon, 4 Aug 2025 19:52:55 +0530
From: Selvarasu Ganesan <selvarasu.g@...sung.com>
To: Thinh.Nguyen@...opsys.com, gregkh@...uxfoundation.org,
m.grzeschik@...gutronix.de, balbi@...com, bigeasy@...utronix.de,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Cc: jh0801.jung@...sung.com, dh10.jung@...sung.com, akash.m5@...sung.com,
hongpooh.kim@...sung.com, eomji.oh@...sung.com, shijie.cai@...sung.com,
alim.akhtar@...sung.com, muhammed.ali@...sung.com, thiagu.r@...sung.com,
stable@...r.kernel.org, Selvarasu Ganesan <selvarasu.g@...sung.com>
Subject: [PATCH] usb: dwc3: Remove WARN_ON for device endpoint command
timeouts
From: Akash M <akash.m5@...sung.com>
This commit addresses a rarely observed endpoint command timeout
which causes kernel panic due to warn when 'panic_on_warn' is enabled
and unnecessary call trace prints when 'panic_on_warn' is disabled.
It is seen during fast software-controlled connect/disconnect testcases.
The following is one such endpoint command timeout that we observed:
1. Connect
=======
->dwc3_thread_interrupt
->dwc3_ep0_interrupt
->configfs_composite_setup
->composite_setup
->usb_ep_queue
->dwc3_gadget_ep0_queue
->__dwc3_gadget_ep0_queue
->__dwc3_ep0_do_control_data
->dwc3_send_gadget_ep_cmd
2. Disconnect
==========
->dwc3_thread_interrupt
->dwc3_gadget_disconnect_interrupt
->dwc3_ep0_reset_state
->dwc3_ep0_end_control_data
->dwc3_send_gadget_ep_cmd
In the issue scenario, in Exynos platforms, we observed that control
transfers for the previous connect have not yet been completed and end
transfer command sent as a part of the disconnect sequence and
processing of USB_ENDPOINT_HALT feature request from the host timeout.
This maybe an expected scenario since the controller is processing EP
commands sent as a part of the previous connect. It maybe better to
remove WARN_ON in all places where device endpoint commands are sent to
avoid unnecessary kernel panic due to warn.
Fixes: e192cc7b5239 ("usb: dwc3: gadget: move cmd_endtransfer to extra function")
Fixes: 72246da40f37 ("usb: Introduce DesignWare USB3 DRD Driver")
Fixes: c7fcdeb2627c ("usb: dwc3: ep0: simplify EP0 state machine")
Fixes: f0f2b2a2db85 ("usb: dwc3: ep0: push ep0state into xfernotready processing")
Fixes: 2e3db064855a ("usb: dwc3: ep0: drop XferNotReady(DATA) support")
Cc: stable@...r.kernel.org
Signed-off-by: Akash M <akash.m5@...sung.com>
Signed-off-by: Selvarasu Ganesan <selvarasu.g@...sung.com>
diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index 666ac432f52d..7b313836f62b 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -288,7 +288,9 @@ void dwc3_ep0_out_start(struct dwc3 *dwc)
dwc3_ep0_prepare_one_trb(dep, dwc->ep0_trb_addr, 8,
DWC3_TRBCTL_CONTROL_SETUP, false);
ret = dwc3_ep0_start_trans(dep);
- WARN_ON(ret < 0);
+ if (ret < 0)
+ dev_warn(dwc->dev, "ep0 out start transfer failed: %d\n", ret);
+
for (i = 2; i < DWC3_ENDPOINTS_NUM; i++) {
struct dwc3_ep *dwc3_ep;
@@ -1061,7 +1063,9 @@ static void __dwc3_ep0_do_control_data(struct dwc3 *dwc,
ret = dwc3_ep0_start_trans(dep);
}
- WARN_ON(ret < 0);
+ if (ret < 0)
+ dev_warn(dwc->dev, "ep0 data phase start transfer failed: %d\n",
+ ret);
}
static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
@@ -1078,7 +1082,12 @@ static int dwc3_ep0_start_control_status(struct dwc3_ep *dep)
static void __dwc3_ep0_do_control_status(struct dwc3 *dwc, struct dwc3_ep *dep)
{
- WARN_ON(dwc3_ep0_start_control_status(dep));
+ int ret;
+
+ ret = dwc3_ep0_start_control_status(dep);
+ if (ret)
+ dev_warn(dwc->dev,
+ "ep0 status phase start transfer failed: %d\n", ret);
}
static void dwc3_ep0_do_control_status(struct dwc3 *dwc,
@@ -1121,7 +1130,10 @@ void dwc3_ep0_end_control_data(struct dwc3 *dwc, struct dwc3_ep *dep)
cmd |= DWC3_DEPCMD_PARAM(dep->resource_index);
memset(¶ms, 0, sizeof(params));
ret = dwc3_send_gadget_ep_cmd(dep, cmd, ¶ms);
- WARN_ON_ONCE(ret);
+ if (ret)
+ dev_warn_ratelimited(dwc->dev,
+ "ep0 data phase end transfer failed: %d\n", ret);
+
dep->resource_index = 0;
}
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 321361288935..50e4f667b2f2 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1774,7 +1774,11 @@ static int __dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force, bool int
dep->flags |= DWC3_EP_DELAY_STOP;
return 0;
}
- WARN_ON_ONCE(ret);
+
+ if (ret)
+ dev_warn_ratelimited(dep->dwc->dev,
+ "end transfer failed: ret = %d\n", ret);
+
dep->resource_index = 0;
if (!interrupt)
@@ -4041,7 +4045,9 @@ static void dwc3_clear_stall_all_ep(struct dwc3 *dwc)
dep->flags &= ~DWC3_EP_STALL;
ret = dwc3_send_clear_stall_ep_cmd(dep);
- WARN_ON_ONCE(ret);
+ if (ret)
+ dev_warn_ratelimited(dwc->dev,
+ "failed to clear STALL on %s\n", dep->name);
}
}
--
2.17.1
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