On Fri, 2 Feb 2018, Peter Chen wrote:

> On Thu, Feb 01, 2018 at 02:24:29PM -0500, Alan Stern wrote:
> > On Thu, 1 Feb 2018, Peter Chen wrote:
> > 
> > > At former code, the SETUP stage does not enable interrupt
> > > for qtd completion, it relies on IAA watchdog to complete
> > > interrupt, then the transcation would be considered timeout
> > > if the flag need_io_watchdog is cleared by platform code.
> > > 
> > > In this commit, we always add enable interrupt for qtd completion,
> > > then the qtd completion can be notified by hardware interrupt.
> > > 
> > > Signed-off-by: Peter Chen <peter.c...@nxp.com>
> > > ---
> > >  drivers/usb/host/ehci-q.c | 6 +++---
> > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > 
> > > diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
> > > index 8815832..4cc2609 100644
> > > --- a/drivers/usb/host/ehci-q.c
> > > +++ b/drivers/usb/host/ehci-q.c
> > > @@ -1192,6 +1192,8 @@ static int submit_single_step_set_feature(
> > >           qtd_fill(ehci, qtd, urb->setup_dma,
> > >                           sizeof(struct usb_ctrlrequest),
> > >                           token | (2 /* "setup" */ << 8), 8);
> > > +         /* Always enable interrupt on qtd completion */
> > > +         qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
> > 
> > This would be cleaner if you didn't make it a separate statement.  
> > Before the call to qtd_fill(), you can do:
> > 
> >             token |= QTD_IOC;       /* Interrupt after SETUP completion */
> 
> Since the variable "token" is used for every qtd, but I do not want
> interrupt for DATA stage, how about adding QTD_IOC directly at
> qtd_fill for both SETUP and STATUS stage?
> 
>               qtd_fill(ehci, qtd, urb->setup_dma,
>                               sizeof(struct usb_ctrlrequest),
>                               QTD_IOC | token | (2 /* "setup" */ << 8), 8);

That would be okay.  You might want to include a comment line as well.

Alan Stern

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