Re: [PATCH v3] usb: dwc2: add bus suspend/resume for dwc2

[Kever Yang]

Hi Paul,

I think you need this patch to fix the problem:

usb: dwc2: resume root hub when device detect with suspend state
https://patchwork.kernel.org/patch/5325111/

Thanks,

- Kever
On 01/06/2015 09:23 AM, Paul Zimmerman wrote:
> > From: Kever Yang [mailto:kever.yang@xxxxxxxxxxxxxx]
> > Sent: Wednesday, November 12, 2014 4:42 PM
> >
> > On 11/13/2014 07:22 AM, Doug Anderson wrote:
> > > Kever,
> > >
> > > On Mon, Nov 10, 2014 at 5:09 AM, Kever Yang <kever.yang@xxxxxxxxxxxxxx> wrote:
> > > > Hcd controller needs bus_suspend/resume, dwc2 controller make
> > > > root hub generate suspend/resume signal with hprt0 register
> > > > when work in host mode.
> > > > After the root hub enter suspend, we can make controller enter
> > > > low power state with PCGCTL register.
> > > >
> > > > We also update the lx_state for hsotg state.
> > > >
> > > > This patch has tested on rk3288 with suspend/resume.
> > > >
> > > > Signed-off-by: Kever Yang <kever.yang@xxxxxxxxxxxxxx>
> > > > Acked-by: Paul Zimmerman <paulz@xxxxxxxxxxxx>
> > > > ---
> > > >
> > > > Changes in v3:
> > > > - remove CONFIG_PM macro for bus_suspend/resume
> > > > - add PCGCTL operation for no device connect case
> > > >
> > > > Changes in v2:
> > > > - update commit message
> > > > - make dwc2 suspend/resume sourcecode work
> > > >
> > > >    drivers/usb/dwc2/hcd.c | 88 +++++++++++++++++++++++++++++++++++++++++++-------
> > > >    1 file changed, 77 insertions(+), 11 deletions(-)
> > > I would certainly appreciate confirmation, but my inclination is to
> > > NAK this change due to the fact that it regresses functionality.  I
> > > haven't done any serious review of it, but I've been testing it and it
> > > appears to break hotplug.
> > >
> > > Said another way, I did this:
> > >
> > > 1. Without this patch, I booted with a USB stick in.  It was detected.
> > > I unplugged it, waited 5 seconds, and then plugged it back in.  The
> > > USB stick was redetcted.
> > >
> > > 2. With this patch, I did the same thing.  The USB not redected after
> > > plugging it back in.
> > With this patch, the dwc2 hcd/root hub will be auto suspend after device
> > on port is disconnected, and it can't detect the device connect any more,
> > I think that's the problem.
> >
> > I will figure out how to make dwc2 detect the device connect after auto
> > suspend,
> > or disable the auto suspend feature for the dwc2 hcd.
> Kever,
>
> This patch has made it into Linus' kernel as commit 0cf884e819e0, and
> it breaks disconnect/connect on at least the Altera SOCFPGA platform.
> I haven't been able to test it on any other platforms.
>
> You need to submit a patch to either fix this, or to only enable this
> feature for the Rock-chip platform. Otherwise the patch has to be
> reverted.


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