Re: [PATCH v2] usb: dwc2: resume root hub when device detect with suspend state
From: Mathias Nyman
Date: Wed Nov 19 2014 - 11:07:45 EST
On 18.11.2014 18:41, Felipe Balbi wrote:
> On Tue, Nov 18, 2014 at 11:07:34AM -0500, Alan Stern wrote:
>> On Tue, 18 Nov 2014, Kever Yang wrote:
>>> After we implement the bus_suspend/resume, auto suspend id enabled.
>>> The root hub will be auto suspend if there is no device connected,
>>> we need to resume the root hub when a device connect detect.
>>> This patch tested on rk3288.
>>> Signed-off-by: Roy Li <roy.li@xxxxxxxxxxxxxx>
>>> Signed-off-by: Kever Yang <kever.yang@xxxxxxxxxxxxxx>
>>> Changes in v2:
>>> - add definition for hcd structure
>>> - remove check for bus->root_hub
>>> drivers/usb/dwc2/hcd_intr.c | 5 +++++
>>> 1 file changed, 5 insertions(+)
>>> diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c
>>> index 551ba87..680206f 100644
>>> --- a/drivers/usb/dwc2/hcd_intr.c
>>> +++ b/drivers/usb/dwc2/hcd_intr.c
>>> @@ -329,6 +329,7 @@ static void dwc2_port_intr(struct dwc2_hsotg *hsotg)
>>> u32 hprt0;
>>> u32 hprt0_modify;
>>> + struct usb_hcd *hcd = (struct usb_hcd *)hsotg->priv;
>>> dev_vdbg(hsotg->dev, "--Port Interrupt--\n");
>>> @@ -354,6 +355,10 @@ static void dwc2_port_intr(struct dwc2_hsotg *hsotg)
>>> hsotg->flags.b.port_connect_status = 1;
>>> hprt0_modify |= HPRT0_CONNDET;
>>> + /* resume root hub? */
>>> + if (hcd->state == HC_STATE_SUSPENDED)
>>> + usb_hcd_resume_root_hub(hcd);
>> You should be aware that it's not safe to use hcd->state for anything
>> in a host controller driver. That field is owned by usbcore, not by
>> the HCD, and it is not protected by any locks.
>> Thus, for example, hcd->state does not get set to HC_STATE_SUSPENDED
>> until some time after the bus_suspend routine has returned. A
>> port-change interrupt might occur during that time interval.
> In that case, XHCI has a bug :-) Mathias, care to add it to your TODO
> list ?
I guess I'll need to check it out, thanks for pointing it out.
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