On 14.09.2018 16:00, Greg KH wrote:
On Fri, Sep 14, 2018 at 03:33:30PM +0300, Mathias Nyman wrote:
From: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
When USB bus host controller root hub resumes from autosuspend,
it immediately tries to enter auto-suspend, but there can be a
scenario when root hub is resuming its usb2 ports, in that particular
case USB host controller auto suspend fails since it is busy
to resuming its usb2 ports.
This makes multiple failed cycles of auto-suspend until all usb2
ports of host controller root hub do not resume.
This patch uses USB core framework usb_hcd_start_port_resume,
usb_hcd_end_port_resume API's in order to autoresume/autosuspend
root hub properly.
Signed-off-by: Anshuman Gupta <anshuman.gupta@xxxxxxxxx>
Signed-off-by: Mathias Nyman <mathias.nyman@xxxxxxxxxxxxxxx>
Not needed in stable? Does this fix a specific commit?
thanks,
greg k-h
This improves a bad initial design that prevented autosuspend by
returning -EBUSY in xhci_bus_suspend() if a usb2 port was resuming.
Instead increment usage count on the roothub to prevent pm from polling
xhci_bus_suspend(). This is also what EHCI does.
I'm not sure If this fixes a actual bug for Anshuman Gupta caused by
the -EBUSY polling,(4.19 +stable), or if this is just a improvement in
suspend/resume code for xhci (4.20).
Anshuman Gupta, any comments?
-Mathias
