Hi, On 8 December 2016 at 19:02, Felipe Balbi <balbi@xxxxxxxxxx> wrote: > > Hi, > > Baolin Wang <baolin.wang@xxxxxxxxxx> writes: >>>> On 28 November 2016 at 14:43, Baolin Wang <baolin.wang@xxxxxxxxxx> wrote: >>>>> For some mobile devices with strict power management, we also want to suspend >>>>> the host when the slave is detached for power saving. Thus we add the host >>>>> suspend/resume functions to support this requirement. >>>>> >>>>> Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx> >>>>> --- >>>>> Changes since v3: >>>>> - No updates. >>>>> >>>>> Changes since v2: >>>>> - Remove pm_children_suspended() and other unused macros. >>>>> >>>>> Changes since v1: >>>>> - Add pm_runtime.h head file to avoid kbuild error. >>>>> --- >>>>> drivers/usb/dwc3/Kconfig | 7 +++++++ >>>>> drivers/usb/dwc3/core.c | 26 +++++++++++++++++++++++++- >>>>> drivers/usb/dwc3/core.h | 15 +++++++++++++++ >>>>> drivers/usb/dwc3/host.c | 37 +++++++++++++++++++++++++++++++++++++ >>>>> 4 files changed, 84 insertions(+), 1 deletion(-) >>>>> >>>>> diff --git a/drivers/usb/dwc3/Kconfig b/drivers/usb/dwc3/Kconfig >>>>> index a45b4f1..47bb2f3 100644 >>>>> --- a/drivers/usb/dwc3/Kconfig >>>>> +++ b/drivers/usb/dwc3/Kconfig >>>>> @@ -47,6 +47,13 @@ config USB_DWC3_DUAL_ROLE >>>>> >>>>> endchoice >>>>> >>>>> +config USB_DWC3_HOST_SUSPEND >>>>> + bool "Choose if the DWC3 host (xhci) can be suspend/resume" >>>>> + depends on USB_DWC3_HOST=y || USB_DWC3_DUAL_ROLE=y >>> >>> why do you need another Kconfig for this? Just enable it already :-p >> >> I assume some platforms may do not need this feature. But okay, I can >> remove this kconfig and enable it. > > thanks :-) > >>>>> diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c >>>>> index 9a4a5e4..7ad4bc3 100644 >>>>> --- a/drivers/usb/dwc3/core.c >>>>> +++ b/drivers/usb/dwc3/core.c >>>>> @@ -1091,6 +1091,7 @@ static int dwc3_probe(struct platform_device *pdev) >>>>> pm_runtime_use_autosuspend(dev); >>>>> pm_runtime_set_autosuspend_delay(dev, DWC3_DEFAULT_AUTOSUSPEND_DELAY); >>>>> pm_runtime_enable(dev); >>>>> + pm_suspend_ignore_children(dev, true); >>> >>> why do you need this? >> >> Since the dwc3 device is the parent deive of xhci device, if we want >> to suspend dwc3 device, we need to suspend child device (xhci device) >> manually by issuing pm_runtime_put_sync() in dwc3_host_suspend(). In >> pm_runtime_put_sync(), it will check if the children (xhci device) of >> dwc3 device have been in suspend state, if not we will suspend dwc3 >> device failed. >> >> We get/put the child device manually in parent device's runtime >> callback, we need to ignore the child device's runtime state, or it >> will failed due to the dependency. > > I see. Good explanation :-) > > There's one thing though, if you want to runtime suspend the gadget and > dwc3 is working on peripheral mode, host side (XHCI) should already be > runtime suspended because there's nothing attached to it. Why isn't it > runtime suspended? Since we have get the runtime count for xHCI device in xhci_plat_probe(), in case it will suspend automatically if some controllers do not want xHCI enters runtime suspend automatically. So the parent device (dwc3 device) need to get/put the xHCI device's runtime count to resume/suspend xHCI. -- Baolin.wang Best Regards -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
