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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

      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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