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From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Paul Menzel <pmenzel@molgen.mpg.de>
Cc: Mathias Nyman <mathias.nyman@intel.com>,
	Mathias Nyman <mathias.nyman@linux.intel.com>,
	George D Sworo <george.d.sworo@intel.com>,
	Matt DeVillier <matt.devillier@gmail.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] xhci: check for a pending command completion during command timeout
Date: Fri, 22 May 2026 12:39:42 +0200	[thread overview]
Message-ID: <2026052218-starboard-reach-5db4@gregkh> (raw)
In-Reply-To: <fdb02568-2267-49b7-bfab-f4159d211863@molgen.mpg.de>

On Fri, May 22, 2026 at 11:35:47AM +0200, Paul Menzel wrote:
> Dear Greg,
> 
> 
> Am 22.05.26 um 11:23 schrieb Greg Kroah-Hartman:
> > On Fri, May 22, 2026 at 10:58:27AM +0200, Paul Menzel wrote:
> > > From: Mathias Nyman <mathias.nyman@linux.intel.com>
> > > 
> > > It's possible a command times out even if xHC hardware already completed
> > > the command. Driver is unaware of the command completion if interrupt
> > > handler is blocked for a long time.
> > > 
> > > Check if there is an unhandled command completion on the event ring during
> > > command timeout.
> > > 
> > > In this case just give the command additional time to complete. There's no
> > > point in aborting the command ring to move past a stuck command.
> > > 
> > > Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> > > Signed-off-by: George D Sworo <george.d.sworo@intel.com>
> > > Link: https://chromium.googlesource.com/chromiumos/third_party/kernel/+/478ab723af9414b0a2a2fbc59ac34f5d319a4fc3
> > > [pmenzel: one adaptation for mainline 7.1: next_trb() uses the
> > >    2-argument form next_trb(&seg, &deq) — the mainline 7.1 signature
> > >    dropped the xhci and ring arguments present in the 6.12 source the
> > >    patch was ported from.  xhci_pending_interrupt() is used directly as
> > >    it is now committed as the preceding prerequisite.]
> > > Assisted-by: Claude Sonnet 4.6
> > > [pmenzel: No devices with the problem available, but no regressions on
> > >    Dell XPS 13 9360 and QEMU 7.2.0.
> > > 
> > >        qemu-system-x86_64 -enable-kvm -cpu host -m 3G -device qemu-xhci,id=xhci -device usb-storage,bus=xhci.0
> > > 
> > >    xHCI host controller initialised cleanly, USB 3.0 SuperSpeed root
> > >    hubs and USB mass storage device enumerated without errors.
> > >    The specific race (command timeout with blocked interrupt handler)
> > >    cannot easily be forced in QEMU, but no regressions in the normal
> > >    command path were observed.]
> > 
> > What are these additions from?  Did you mean to send these out to the
> > lists?
> 
> Yes, they are authored by me and meant for the list. I wanted to document,
> where I got the patch from and how I tested the change. Feel free to remove
> them.

These make no sense, please remove them yourself and resend.

thanks,

greg k-h

  reply	other threads:[~2026-05-22 10:39 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-05-22  8:58 [PATCH 1/2] xhci: add helper to check for pending interrupt Paul Menzel
2026-05-22  8:58 ` [PATCH 2/2] xhci: check for a pending command completion during command timeout Paul Menzel
2026-05-22  9:23   ` Greg Kroah-Hartman
2026-05-22  9:35     ` Paul Menzel
2026-05-22 10:39       ` Greg Kroah-Hartman [this message]
2026-05-22 11:11         ` Mathias Nyman
2026-05-22 12:38           ` Paul Menzel

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