Linux USB
 help / color / mirror / Atom feed
From: Alan Stern <stern@rowland.harvard.edu>
To: Troels Liebe Bentsen <troels@connectedcars.dk>
Cc: Hans Petter Selasky <hps@selasky.org>,
	Greg KH <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org
Subject: Re: All USB tools hang when one descriptor read fails and needs to timeout
Date: Thu, 26 Jan 2023 11:23:42 -0500	[thread overview]
Message-ID: <Y9KpDvYEag++ec4t@rowland.harvard.edu> (raw)
In-Reply-To: <CAHHqYPPh43XccGvA6Dt9Ofy7PoXJsJxQvZDVima671Kq1bOn1Q@mail.gmail.com>

On Thu, Jan 26, 2023 at 04:26:24PM +0100, Troels Liebe Bentsen wrote:
> But that's another question, how do I get Linux to re-enumerating the
> device and update the sysfs files?

You can force a device reset using libusb or the usb-reset program 
floating around the Internet.  After the kernel resets a device, it 
checks to make sure the device, BOS, configuration, and serial-number 
string descriptors have not changed.  If any of them is different from 
what it used to be, the kernel will re-enumerate the device.

Or, you can get the same effect by unplugging the device and then 
plugging it back in.  But with direct-wired connections, that's not 
possible.

Alan Stern

  reply	other threads:[~2023-01-26 16:24 UTC|newest]

Thread overview: 20+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-26 11:49 All USB tools hang when one descriptor read fails and needs to timeout Troels Liebe Bentsen
2023-01-26 12:23 ` Greg KH
2023-01-26 13:06   ` Troels Liebe Bentsen
2023-01-26 13:12     ` Greg KH
2023-01-26 13:59       ` Troels Liebe Bentsen
2023-01-26 14:27         ` Hans Petter Selasky
2023-01-26 15:26           ` Troels Liebe Bentsen
2023-01-26 16:23             ` Alan Stern [this message]
2023-01-26 16:17         ` Alan Stern
2023-01-27 14:12           ` Troels Liebe Bentsen
2023-01-27 16:07             ` Alan Stern
2023-01-31 15:59               ` Troels Liebe Bentsen
2023-01-31 20:41                 ` Alan Stern
2023-01-31 20:56                   ` Greg KH
2023-02-07  8:25                     ` Troels Liebe Bentsen
2023-02-07  8:33                       ` Troels Liebe Bentsen
2023-02-07 17:52                       ` Alan Stern
2023-02-08 16:48                         ` Alan Stern
2023-02-08 20:46                           ` Troels Liebe Bentsen
2023-02-08 21:57                             ` Alan Stern

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=Y9KpDvYEag++ec4t@rowland.harvard.edu \
    --to=stern@rowland.harvard.edu \
    --cc=gregkh@linuxfoundation.org \
    --cc=hps@selasky.org \
    --cc=linux-usb@vger.kernel.org \
    --cc=troels@connectedcars.dk \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox