From: Alan Stern <stern@rowland.harvard.edu>
To: "Yo-Jung (Leo) Lin" <leo.lin@canonical.com>
Cc: gregkh@linuxfoundation.org, rafael@kernel.org, pavel@ucw.cz,
len.brown@intel.com, bhelgaas@google.com,
duanchenghao@kylinos.cn, dlemoal@kernel.org,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-pm@vger.kernel.org, hdegoede@redhat.com
Subject: Re: [PATCH] USB: Prevent xhci from resuming root hub during suspend entrance
Date: Fri, 10 Jan 2025 10:44:52 -0500 [thread overview]
Message-ID: <b16e2b38-e9f8-43af-9df0-0510895c02ee@rowland.harvard.edu> (raw)
In-Reply-To: <20250110084413.80981-1-leo.lin@canonical.com>
On Fri, Jan 10, 2025 at 04:44:10PM +0800, Yo-Jung (Leo) Lin wrote:
> The commit d9b4067aef50 ("USB: Fix the issue of task recovery failure
> caused by USB status when S4 wakes up") fixed an issue where if an USB
> port change happens during the entering steps of hibernation, xhci driver
> would attempt to resume the root hub, making the hibernation fail.
>
> System-wide suspend may fail due to the same reason, but this hasn't been
> addressed yet. This has been found on HP ProOne 440[1], as well as on
> some newer Dell all-in-one models. When suspend fails due to this reason,
> the kernel would show the following messages:
I believe this problem was discussed on the mailing list before, and it
turned out that the issue was caused by a bug in the xhci-hcd driver,
not a bug in the USB core.
Basically, suspend is _supposed_ to fail if a wakeup event occurs while
the suspend is in progress. As I recall, the bug in xhci-hcd was that
it treats some non-wakeup events as if they were wakeup events.
In particular, a port change on the root hub should be treated as a
wakeup event if and only if the root hub is enabled for wakeup. Does
xhci-hcd check for this before failing the suspend?
This reasoning shows that your proposed fix is incorrect.
Alan Stern
next prev parent reply other threads:[~2025-01-10 15:44 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-01-10 8:44 [PATCH] USB: Prevent xhci from resuming root hub during suspend entrance Yo-Jung (Leo) Lin
2025-01-10 8:54 ` Greg KH
2025-01-10 15:44 ` Alan Stern [this message]
2025-01-13 8:14 ` Yo-Jung (Leo) Lin
2025-01-13 16:03 ` 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=b16e2b38-e9f8-43af-9df0-0510895c02ee@rowland.harvard.edu \
--to=stern@rowland.harvard.edu \
--cc=bhelgaas@google.com \
--cc=dlemoal@kernel.org \
--cc=duanchenghao@kylinos.cn \
--cc=gregkh@linuxfoundation.org \
--cc=hdegoede@redhat.com \
--cc=len.brown@intel.com \
--cc=leo.lin@canonical.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=linux-usb@vger.kernel.org \
--cc=pavel@ucw.cz \
--cc=rafael@kernel.org \
/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