[Quantal][SRU][PATCH 2/2] usb: xhci: add USB2 Link power management BESL support

[Tim Gardner]

On 09/26/2013 02:32 AM, Shawn Wang wrote:
> Hi Tim,
>  The original commit a558ccdcc71c7770c5e80c926a31cfe8a3892a09
> add usb2_hw_lpm_besl_capable in struct 
>  usb3_lpm_parameters. (include/linux/usb.h)
>  However, the XHCI_HLC and XHCI_BLC are the same.
>  We skip the below change, use usb2_hw_lpm_capable to instead of
> usb2_hw_lpm_besl_capable.
>  If add dcf06a036848b4e8e6c8220f2e00b9adf6f84918, should we change the
> struct usb3_lpm_parameters?
> 
>  Some realtek webcam modules need the backport to fix preview issues.
> 
> a558ccdcc71c7770c5e80c926a31cfe8a3892a09
> 
>  +++ b/drivers/usb/host/xhci-ext-caps.h
>   @@ -71,6 +71,7 @@
>   
>    /* USB 2.0 xHCI 1.0 hardware LMP capability - section 7.2.2.1.3.2 */
>    #define XHCI_HLC               (1 << 19)
>   +#define XHCI_BLC               (1 << 19)
> 
>   @@ -4068,6 +4191,9 @@ int xhci_update_device(struct usb_hcd *hcd,
> struct usb_device *udev)
>           if (xhci->hw_lpm_support == 1 &&
>               xhci_check_usb2_port_capability(xhci, portnum, XHCI_HLC)) {
>               udev->usb2_hw_lpm_capable = 1;
>   +           if (xhci_check_usb2_port_capability(xhci, portnum,
>   +                               XHCI_BLC))
>   +               udev->usb2_hw_lpm_besl_capable = 1;
> 
> 
> dcf06a036848b4e8e6c8220f2e00b9adf6f84918
> 
>  /* USB 2.0 xHCI 1.0 hardware LMP capability - section 7.2.2.1.3.2 */
>  #define XHCI_HLC               (1 << 19)
> -#define XHCI_BLC               (1 << 19)
> +#define XHCI_BLC               (1 << 20)
> 
> Regards,
> Shawn
> 

Ah, never mind. The back port of
a558ccdcc71c7770c5e80c926a31cfe8a3892a09 looks OK. However, there is no
mention in the bug report of any kind of regression tests having been
performed. This looks like a code path that will affect a lot of devices.

rtg
-- 
Tim Gardner tim.gardner at canonical.com