On Fri, Apr 11, 2014 at 03:50:05PM +0530, Pratyush Anand wrote:
> As best case, a host controller should support U0 to U1 switching for
> the devices connected below any tier of hub level supported by usb
> specification. Therefore xhci_check_default_tier_policy always returns
> success.
>
> A host should be able to issue LGO_Ux after the timeout calculated as
> per definition of system exit latency defined in C.1.5.2. Therefore
> xhci_calculate_default_ux_timeout returns ux_params.sel as the default
> implementation.
>
> Use default calculation in absence of any vendor specific limitations.
>
> Signed-off-by: Pratyush Anand <pratyush.anand@xxxxxx>
> ---
> drivers/usb/host/xhci.c | 61 +++++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
> index 6cc58fe..930c01f 100644
> --- a/drivers/usb/host/xhci.c
> +++ b/drivers/usb/host/xhci.c
> @@ -4140,6 +4140,53 @@ static u16 xhci_get_timeout_no_hub_lpm(struct usb_device *udev,
> return USB3_LPM_DISABLED;
> }
>
> +/* Returns the default hub-encoded U1 timeout value.
> + */
fits in one line
> +static u16 xhci_calculate_default_u1_timeout(struct usb_device *udev,
> + struct usb_endpoint_descriptor *desc)
> +{
> + unsigned long long timeout_ns;
> +
> + timeout_ns = udev->u1_params.sel;
> +
> + /* The U1 timeout is encoded in 1us intervals. */
> + timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 1000);
> + /* Don't return a timeout of zero, because that's USB3_LPM_DISABLED. */
> + if (timeout_ns == USB3_LPM_DISABLED)
will this *ever* happen ? you're using DIV_ROUND_UP...
> + timeout_ns++;
> +
> + /* If the necessary timeout value is bigger than what we can set in the
> + * USB 3.0 hub, we have to disable hub-initiated U1.
> + */
> + if (timeout_ns <= USB3_LPM_U1_MAX_TIMEOUT)
> + return timeout_ns;
> + dev_dbg(&udev->dev, "Hub-initiated U1 disabled "
> + "due to long timeout %llu ms\n", timeout_ns);
> + return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U1);
> +}
> +
> +/* Returns the default hub-encoded U2 timeout value.
> + */
> +static u16 xhci_calculate_default_u2_timeout(struct usb_device *udev,
> + struct usb_endpoint_descriptor *desc)
> +{
> + unsigned long long timeout_ns;
> +
> + timeout_ns = udev->u2_params.sel;
> +
> + /* The U2 timeout is encoded in 256us intervals */
> + timeout_ns = DIV_ROUND_UP_ULL(timeout_ns, 256 * 1000);
> + /* If the necessary timeout value is bigger than what we can set in the
> + * USB 3.0 hub, we have to disable hub-initiated U2.
> + */
> + if (timeout_ns <= USB3_LPM_U2_MAX_TIMEOUT)
> + return timeout_ns;
> + dev_dbg(&udev->dev, "Hub-initiated U2 disabled "
> + "due to long timeout %llu ms\n", timeout_ns);
> + return xhci_get_timeout_no_hub_lpm(udev, USB3_LPM_U2);
this function is mostly duplicated with default_u1, perhaps refactor it
a bit and pass one extra argument which will tell you if you're
calculating U1 or U2 ?
--
balbi
Attachment:
signature.asc
Description: Digital signature
