Messages in this thread Patch in this message | | | Subject | Re: [PATCH] USB: Don't enable LPM if it's already enabled | From | Mathias Nyman <> | Date | Tue, 30 Oct 2018 16:24:08 +0200 |
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On 30.10.2018 07:54, Kai-Heng Feng wrote: > USB Bluetooth controller QCA ROME (0cf3:e007) sometimes stops working > after S3: > [ 165.110742] Bluetooth: hci0: using NVM file: qca/nvm_usb_00000302.bin > [ 168.432065] Bluetooth: hci0: Failed to send body at 4 of 1953 (-110) > > After some experiments, I found that disabling LPM can workaround the > issue. > > On some platforms, the USB power is cut during S3, so the driver uses > reset-resume to resume the device. During port resume, LPM gets enabled > twice, by usb_reset_and_verify_device() and usb_port_resume(). > > So let's enable LPM for just once, as this solves the issue for the > device in question. > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > drivers/usb/core/driver.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c > index 53564386ed57..e11d2eac76b6 100644 > --- a/drivers/usb/core/driver.c > +++ b/drivers/usb/core/driver.c > @@ -1901,7 +1901,8 @@ int usb_set_usb2_hardware_lpm(struct usb_device *udev, int enable) > struct usb_hcd *hcd = bus_to_hcd(udev->bus); > int ret = -EPERM; > > - if (enable && !udev->usb2_hw_lpm_allowed) > + if (enable && !udev->usb2_hw_lpm_allowed || > + udev->usb2_hw_lpm_enabled == enable) > return 0; > > if (hcd->driver->set_usb2_hw_lpm) { >
Something like that would probably work.
Would it make sense to skip USB2 hw LPM enabling in usb_port_resume() if port was just reset (and thus LPM enabled)?
something like this:
--- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -3520,7 +3520,7 @@ int usb_port_resume(struct usb_device *udev, pm_message_t msg) hub_port_logical_disconnect(hub, port1); } else { /* Try to enable USB2 hardware LPM */ - if (udev->usb2_hw_lpm_capable == 1) + if (udev->usb2_hw_lpm_capable == 1 && !udev->reset_resume) usb_set_usb2_hardware_lpm(udev, 1); /* Try to enable USB3 LTM */ -Mathias
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