RE: [PATCH v2 14/32] usb: dwc2: host: wait 3ms for controller stabilization

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> -----Original Message-----
> From: Sergei Shtylyov [mailto:sergei.shtylyov@xxxxxxxxxxxxxxxxxx]
> Sent: Tuesday, September 22, 2015 9:42 PM
> To: Kaukab, Yousaf; linux-usb@xxxxxxxxxxxxxxx; balbi@xxxxxx;
> john.youn@xxxxxxxxxxxx; Herrero, Gregory
> Cc: heiko@xxxxxxxxx; dianders@xxxxxxxxxxxx; r.baldyga@xxxxxxxxxxx;
> dinguyen@xxxxxxxxxxxxxxxxxxxxx; zhangfei.gao@xxxxxxxxxx;
> david.a.cohen@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v2 14/32] usb: dwc2: host: wait 3ms for controller
> stabilization
> 
> On 09/22/2015 04:16 PM, Mian Yousaf Kaukab wrote:
> 
> > From: Gregory Herrero <gregory.herrero@xxxxxxxxx>
> >
> > Some high speed mass storage devices fail to enumerate with following
> > error:
> >
> > Cannot enable port %i.  Maybe the USB cable is bad?
> >
> > This happens only when the device is plugged while the controller is
> > in hibernation state. After exiting hibernation, the controller
> > detects the device as a low speed device and fail to enumerate it.
> >
> > Problem occurs only if HPRT0.PWR bit is programmed in a too short
> > delay after exiting hibernation. Dumping hprt register in
> > _dwc2_hcd_resume() directly after dwc2_exit_hibernation() shows that
> > HPRT0.LNSTS (D+/D- level) becomes valid approximately 2ms after
> > exiting hibernation.
> 
> > Since dwc2_exit_hibernation() is called from atomic context, move the
> > delay out of this function.
> 
>     Hm, I don't see Gregory moving anything in this patch...
> 
Perhaps keep is more appropriate word. I'll replace move with keep if
I end up doing another revision of this series.

BR,
Yousaf

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