[lkml]   [2018]   [Apr]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [PATCH V5] USB: Increment wakeup count on remote wakeup.
Sure. Pushing it to the older kernels will definitely help.


On Sat, Apr 21, 2018 at 1:59 AM, Greg KH <> 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
>> The upstream facing port then sets C_PORT_SUSPEND bit and reports a
>> port change event (USB 2.0 spec section 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 Thus on receiving the Function Wake, increment the
>> wakeup count.
>> Signed-off-by: Ravi Chandra Sadineni <>
>> ---
>> 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

 \ /
  Last update: 2018-04-21 15:39    [W:0.054 / U:1.872 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site