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SubjectRe: [PATCH v3] USB: Don't enable LPM if it's already enabled
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> On Dec 3, 2018, at 4:32 PM, Kai-Heng Feng <kai.heng.feng@canonical.com> 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.

Please ignore this patch, I missed Greg’s suggestion to use _enable() and _disable() naming.

Will send a v4.

Kai-Heng

>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
> ---
> v3:
> - Consolidate udev->usb2_hw_lpm_capable and udev->usb2_hw_lpm_enabled
> check to usb_set_usb2_hardware_lpm().
> v2:
> - Check udev->usb2_hw_lpm_enabled before calling usb_port_resume().
>
> drivers/usb/core/driver.c | 4 +++-
> drivers/usb/core/hub.c | 13 ++++---------
> drivers/usb/core/message.c | 3 +--
> 3 files changed, 8 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/usb/core/driver.c b/drivers/usb/core/driver.c
> index 53564386ed57..f277a8de7498 100644
> --- a/drivers/usb/core/driver.c
> +++ b/drivers/usb/core/driver.c
> @@ -1901,7 +1901,9 @@ 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 (!udev->usb2_hw_lpm_capable ||
> + (enable && !udev->usb2_hw_lpm_allowed) ||
> + (enable && udev->usb2_hw_lpm_enabled))
> return 0;
>
> if (hcd->driver->set_usb2_hw_lpm) {
> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index e482e5f103d9..907793d38a82 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -3210,8 +3210,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
> }
>
> /* disable USB2 hardware LPM */
> - if (udev->usb2_hw_lpm_enabled == 1)
> - usb_set_usb2_hardware_lpm(udev, 0);
> + usb_set_usb2_hardware_lpm(udev, 0);
>
> if (usb_disable_ltm(udev)) {
> dev_err(&udev->dev, "Failed to disable LTM before suspend\n");
> @@ -3249,8 +3248,7 @@ int usb_port_suspend(struct usb_device *udev, pm_message_t msg)
> usb_enable_ltm(udev);
> err_ltm:
> /* Try to enable USB2 hardware LPM again */
> - if (udev->usb2_hw_lpm_capable == 1)
> - usb_set_usb2_hardware_lpm(udev, 1);
> + usb_set_usb2_hardware_lpm(udev, 1);
>
> if (udev->do_remote_wakeup)
> (void) usb_disable_remote_wakeup(udev);
> @@ -3533,9 +3531,7 @@ 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 &&
> - !udev->usb2_hw_lpm_enabled)
> - usb_set_usb2_hardware_lpm(udev, 1);
> + usb_set_usb2_hardware_lpm(udev, 1);
>
> /* Try to enable USB3 LTM */
> usb_enable_ltm(udev);
> @@ -5639,8 +5635,7 @@ static int usb_reset_and_verify_device(struct usb_device *udev)
> /* Disable USB2 hardware LPM.
> * It will be re-enabled by the enumeration process.
> */
> - if (udev->usb2_hw_lpm_enabled == 1)
> - usb_set_usb2_hardware_lpm(udev, 0);
> + usb_set_usb2_hardware_lpm(udev, 0);
>
> /* Disable LPM while we reset the device and reinstall the alt settings.
> * Device-initiated LPM, and system exit latency settings are cleared
> diff --git a/drivers/usb/core/message.c b/drivers/usb/core/message.c
> index bfa5eda0cc26..a00952bdf645 100644
> --- a/drivers/usb/core/message.c
> +++ b/drivers/usb/core/message.c
> @@ -1243,8 +1243,7 @@ void usb_disable_device(struct usb_device *dev, int skip_ep0)
> dev->actconfig->interface[i] = NULL;
> }
>
> - if (dev->usb2_hw_lpm_enabled == 1)
> - usb_set_usb2_hardware_lpm(dev, 0);
> + usb_set_usb2_hardware_lpm(dev, 0);
> usb_unlocked_disable_lpm(dev);
> usb_disable_ltm(dev);
>
> --
> 2.17.1
>

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