lkml.org 
[lkml]   [2018]   [Nov]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v2] USB: Don't enable LPM if it's already enabled
From
Date
Hi Greg,

> On Oct 31, 2018, at 1:52 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.
>
> Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>

Would it be possible to merge this patch?

Kai-Heng

> ---
> 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);
>
> /* Try to enable USB3 LTM */
> --
> 2.19.1
>

\
 
 \ /
  Last update: 2018-11-23 07:04    [W:0.108 / U:0.984 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site