From: Greg KH <gregkh@linuxfoundation.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Oliver Neukum <oneukum@suse.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
Jiri Slaby <jirislaby@kernel.org>,
linux-serial@vger.kernel.org
Subject: Re: USB cdc-acm driver: break and command
Date: Wed, 16 Jul 2025 08:58:10 +0200 [thread overview]
Message-ID: <2025071652-afar-cornhusk-0830@gregkh> (raw)
In-Reply-To: <ce54ae11-72bb-4ac7-980b-c1cbc798a209@zytor.com>
On Tue, Jul 15, 2025 at 02:00:10PM -0700, H. Peter Anvin wrote:
> Hi,
>
> I noticed looking at the CDC-ACM driver that it uses the assert/local
> delay/deassert method of sending BREAK. Given that the CDC model has a
> delay specifier in the command packet, is there any reason not to set
> TTY_DRIVER_HARDWARE_BREAK and sending only one packet?
>
> I'm also wondering if it would make sense to support the
> SEND_ENCAPSULATED_COMMAND and GET_ENCAPSULATED_RESPONSE commands, presumably
> via an ioctl(). I'm not 100% sure because I'm not sure there aren't
> potential security issues.
>
> I'm guessing both of these could be of some use to embedded devices that
> emulate a ttyACM serial port.
No idea why this is that way, sorry. Try making the change and see if
it actually works?
thanks,
greg k-h
next prev parent reply other threads:[~2025-07-16 6:58 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-07-15 21:00 USB cdc-acm driver: break and command H. Peter Anvin
2025-07-16 6:58 ` Greg KH [this message]
2025-07-16 8:29 ` Oliver Neukum
2025-07-16 15:06 ` H. Peter Anvin
2025-07-16 16:17 ` Oliver Neukum
2025-07-16 17:30 ` H. Peter Anvin
2025-07-17 11:32 ` Oliver Neukum
2025-07-16 17:49 ` H. Peter Anvin
2025-07-17 11:28 ` Oliver Neukum
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