On Wed, Oct 31, 2018 at 01:52:09PM +0800, 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.f...@canonical.com>
> ---
> v2:
> - Check udev->usb2_hw_lpm_enabled before calling usb_port_resume().
>
> drivers/usb/core/hub.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index c6077d582d29..02fa574e98ce 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -3523,7 +3523,8 @@ 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->usb2_hw_lpm_enabled)
> usb_set_usb2_hardware_lpm(udev, 1);
It's annoying how every caller has to try to figure this out, why can't
we put this logic in the usb_set_usb2_hardware_lpm() itself?
And usb_set_usb2_hardware_lpm() is a horrid name, as it has a bool
option that you always have to look up. We should just have
usb_usb2_hardware_lpm_enable() and usb_usb2_hardware_lpm_disable().
Care to make this a patch series to fix all of this up?
thanks,
greg k-h
