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From: Ravi Chandra Sadineni <ravisadineni@google.com>
To: Greg KH <gregkh@linuxfoundation.org>
Cc: Ravi Chandra Sadineni <ravisadineni@chromium.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	chunfeng.yun@mediatek.com, johan@kernel.org,
	Arvind Yadav <arvind.yadav.cs@gmail.com>,
	Dmitry Torokhov <dtor@google.com>,
	Anton Bondarenko <anton.bondarenko.sama@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	mathias.nyman@linux.intel.com, felipe.balbi@linux.intel.com,
	Eugene Korenevsky <ekorenevsky@gmail.com>,
	peter.chen@nxp.com, joe@perches.com,
	Todd Broch <tbroch@google.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Rajat Jain <rajatja@google.com>, Benson Leung <bleung@google.com>
Subject: Re: [PATCH V5] USB: Increment wakeup count on remote wakeup.
Date: Sat, 21 Apr 2018 06:37:46 -0700	[thread overview]
Message-ID: <CAOGSYL00=h-1x=jWuYQ8ucuOE79KN-17L-cCt8Tf1nCNioQxwA@mail.gmail.com> (raw)
In-Reply-To: <20180421085956.GA8081@kroah.com>

Sure. Pushing it to the older kernels will definitely help.

Thanks,
Ravi

On Sat, Apr 21, 2018 at 1:59 AM, Greg KH <gregkh@linuxfoundation.org> wrote:
> On Fri, Apr 20, 2018 at 11:08:21AM -0700, Ravi Chandra Sadineni wrote:
>> On chromebooks we depend on wakeup count to identify the wakeup source.
>> But currently USB devices do not increment the wakeup count when they
>> trigger the remote wake. This patch addresses the same.
>>
>> Resume condition is reported differently on USB 2.0 and USB 3.0 devices.
>>
>> On USB 2.0 devices, a wake capable device, if wake enabled, drives
>> resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
>> The upstream facing port then sets C_PORT_SUSPEND bit and reports a
>> port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
>> has resumed before driving the resume signal from the host and
>> C_PORT_SUSPEND is set, then the device attached to the given port might
>> be the reason for the last system wakeup. Increment the wakeup count for
>> the same.
>>
>> On USB 3.0 devices, a function may signal that it wants to exit from device
>> suspend by sending a Function Wake Device Notification to the host (USB3.0
>> spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
>> wakeup count.
>>
>> Signed-off-by: Ravi Chandra Sadineni <ravisadineni@chromium.org>
>> ---
>>
>> V5: Added the description of changes between different versions of patches.
>> V4: Moved the wakeup count increment logic to the existing if which is
>> safegaurded by hcd_root_hub_lock spinlock.
>> V3: Added a gaurd to check if rh_registered is set before accessing
>> root_hub pointer.
>> V2: Fixed the build failure error due to uninitialized dev pointer.
>
> Is this needed in older kernels?  Should I submit it to the stable
> trees?
>
> thanks,
>
> greg k-h

  reply	other threads:[~2018-04-21 13:38 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-19  0:18 [PATCH] " Ravi Chandra Sadineni
2018-04-19  9:30 ` kbuild test robot
2018-04-19  9:33 ` kbuild test robot
2018-04-19 15:01 ` Alan Stern
2018-04-19 16:17   ` Rajat Jain
2018-04-20  0:27   ` [PATCH V2] " Ravi Chandra Sadineni
2018-04-20 14:12     ` Alan Stern
2018-04-20 17:05       ` [PATCH V3] " Ravi Chandra Sadineni
2018-04-20 17:29         ` Alan Stern
2018-04-20 17:54           ` [PATCH V4] " Ravi Chandra Sadineni
2018-04-20 18:08           ` [PATCH V5] " Ravi Chandra Sadineni
2018-04-20 18:22             ` Alan Stern
2018-04-21  8:59             ` Greg KH
2018-04-21 13:37               ` Ravi Chandra Sadineni [this message]
2018-04-20 18:12           ` [PATCH V3] " Ravi Chandra Sadineni
2018-04-20 17:07       ` [PATCH V2] " Ravi Chandra Sadineni
2018-04-20  0:50   ` [PATCH] " Ravi Chandra Sadineni

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