From: Greg KH <gregkh@linuxfoundation.org>
To: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: stern@rowland.harvard.edu, mr.yming81@gmail.com,
chunfeng.yun@mediatek.com, matthias.bgg@gmail.com,
nishadkamdar@gmail.com, linux-usb@vger.kernel.org,
linux-kernel@vger.kernel.org,
linux-arm-kernel@lists.infradead.org,
linux-mediatek@lists.infradead.org, eddie.hung@mediatek.com
Subject: Re: [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing roothub power-on-good delay
Date: Sat, 6 Nov 2021 15:41:47 +0100 [thread overview]
Message-ID: <YYaUK/rjuAOucOpI@kroah.com> (raw)
In-Reply-To: <b5b59fb7-40ce-929e-479a-d0605994cb53@linux.intel.com>
On Fri, Nov 05, 2021 at 09:56:59PM +0200, Mathias Nyman wrote:
> On 5.11.2021 18.15, Greg KH wrote:
> > On Fri, Nov 05, 2021 at 06:00:36PM +0200, Mathias Nyman wrote:
> >> Some USB 3.1 enumeration issues were reported after the hub driver removed
> >> the minimum 100ms limit for the power-on-good delay.
> >>
> >> Since commit 90d28fb53d4a ("usb: core: reduce power-on-good delay time of
> >> root hub") the hub driver sets the power-on-delay based on the
> >> bPwrOn2PwrGood value in the hub descriptor.
> >>
> >> xhci driver has a 20ms bPwrOn2PwrGood value for both roothubs based
> >> on xhci spec section 5.4.8, but it's clearly not enough for the
> >> USB 3.1 devices, causing enumeration issues.
> >>
> >> Tests indicate full 100ms delay is needed.
> >>
> >> Reported-by: Walt Jr. Brake <mr.yming81@gmail.com>
> >> Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
> >
> > So this needs:
> > Fixes: 90d28fb53d4a ("usb: core: reduce power-on-good delay time of root hub")
> > right?
>
> I guess so, not sure on "Fixes" policy here.
>
> This patch fixes an xhci issue revealed by ("usb: core: reduce power-on-good delay time of root hub")
> That original patch itself looks correct, but these two patches should really go together to
> avoid any enumeration issues.
Great, I'll use that tag for now so that it will get backported
properly.
greg k-h
prev parent reply other threads:[~2021-11-06 14:41 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-10 1:20 [PATCH v2] usb: core: reduce power-on-good delay time of root hub Chunfeng Yun
2021-11-01 3:33 ` Walt Jr. Brake
[not found] ` <5e907ccd-40bb-2ece-fe05-1a65a74f3aa2@gmail.com>
2021-11-01 14:06 ` Alan Stern
2021-11-02 9:05 ` Mathias Nyman
2021-11-02 20:29 ` Walt Jr. Brake
2021-11-03 20:37 ` Mathias Nyman
2021-11-05 10:00 ` Greg Kroah-Hartman
2021-11-05 13:30 ` Alan Stern
2021-11-05 16:00 ` [PATCH] xhci: Fix USB 3.1 enumeration issues by increasing roothub power-on-good delay Mathias Nyman
2021-11-05 16:09 ` Mathias Nyman
2021-11-05 17:32 ` Walt Jr. Brake
2021-11-05 19:41 ` Mathias Nyman
2021-11-05 16:15 ` Greg KH
2021-11-05 19:56 ` Mathias Nyman
2021-11-06 14:41 ` Greg KH [this message]
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