linux-kernel - Re: [PATCH v3] platform/x86/hp: Avoid spurious wakeup on HP ProOne 440

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <d8600868-6e4b-45ab-b328-852b6ac8ecb5@rowland.harvard.edu>
Date: Fri, 6 Sep 2024 10:22:14 -0400
From: Alan Stern <stern@...land.harvard.edu>
To: Kai-Heng Feng <kai.heng.feng@...onical.com>,
	Mathias Nyman <mathias.nyman@...ux.intel.com>
Cc: hdegoede@...hat.com, ilpo.jarvinen@...ux.intel.com,
	gregkh@...uxfoundation.org, jorge.lopez2@...com,
	acelan.kao@...onical.com, platform-driver-x86@...r.kernel.org,
	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org
Subject: Re: [PATCH v3] platform/x86/hp: Avoid spurious wakeup on HP ProOne
 440

On Fri, Sep 06, 2024 at 01:30:47PM +0800, Kai-Heng Feng wrote:
> The HP ProOne 440 has a power saving design that when the display is
> off, it also cuts the USB touchscreen device's power off.
> 
> This can cause system early wakeup because cutting the power off the
> touchscreen device creates a disconnect event and prevent the system
> from suspending:

Is the touchscreen device connected directly to the root hub?  If it is 
then it looks like there's a separate bug here, which needs to be fixed.

> [  445.814574] hub 2-0:1.0: hub_suspend
> [  445.814652] usb usb2: bus suspend, wakeup 0

Since the wakeup flag is set to 0, the root hub should not generate a 
wakeup request when a port-status-change event happens.

> [  445.824629] xhci_hcd 0000:00:14.0: Port change event, 1-11, id 11, portsc: 0x202a0
> [  445.824639] xhci_hcd 0000:00:14.0: resume root hub

But it did.  This appears to be a bug in one of the xhci-hcd suspend 
routines.

Alternatively, if the touchscreen device is connected to an intermediate 
hub then that intermediate hub should not be allowed to generate wakeup 
events.  That's determined by userspace, though, not by the kernel.

Alan Stern