From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Kuen-Han Tsai <khtsai@google.com>
Cc: Mathias Nyman <mathias.nyman@linux.intel.com>,
Alan Stern <stern@rowland.harvard.edu>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] usb: core: Add tracepoints for device allocation and state changes
Date: Tue, 14 Oct 2025 09:57:24 +0200 [thread overview]
Message-ID: <2025101446-starved-brownnose-e9ed@gregkh> (raw)
In-Reply-To: <20251013-usbcore-tracing-v1-2-b885a3121b09@google.com>
On Mon, Oct 13, 2025 at 10:01:23AM +0800, Kuen-Han Tsai wrote:
> Introduce new tracepoints to the USB core to improve debuggability of
> USB device lifecycle events.
>
> The following tracepoints are added:
>
> - usb_alloc_dev: Triggered when a new USB device structure is allocated,
> providing insights into early device setup.
> - usb_set_device_state: Triggered when the USB device state changes,
> allowing observation of the device's state transitions.
>
> These tracepoints capture detailed information about the USB device,
> including its name, speed, state, bus current value, and authorized
> flag. This will aid developers in diagnosing issues related to device
> enumeration within the USB subsystem.
>
> Examples:
> usb_alloc_dev: usb 1-1 speed 0 state 1 0mA [authorized]
If you are going to change the state to be a string, can you also change
the speed to be a string as well? That will help out with people
wondering what is going on with the speed of the device a lot.
thanks,
greg k-h
next prev parent reply other threads:[~2025-10-14 7:57 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-13 2:01 [PATCH 0/2] usb: core: Improve device lifecycle debuggability Kuen-Han Tsai
2025-10-13 2:01 ` [PATCH 1/2] usb: core: Centralize device state update logic Kuen-Han Tsai
2025-10-13 13:16 ` Alan Stern
2025-10-14 0:06 ` Kuen-Han Tsai
2025-10-13 2:01 ` [PATCH 2/2] usb: core: Add tracepoints for device allocation and state changes Kuen-Han Tsai
2025-10-13 13:20 ` Alan Stern
2025-10-14 0:05 ` Kuen-Han Tsai
2025-10-14 3:24 ` Alan Stern
2025-10-14 5:17 ` Greg Kroah-Hartman
2025-10-14 7:57 ` Greg Kroah-Hartman [this message]
2025-10-14 19:37 ` Kuen-Han Tsai
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