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@xxxxxxxxxxxx> > --- > > 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 -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
