Re: [PATCH 4/5] usb: ehci-hcd: use mdelay_non_inerruptible()

[Peter Mamonov <pmamonov@gmail.com>]

On Wed, 7 Oct 2015 15:47:03 +0200
Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com> wrote:

> On 18:58 Tue 22 Sep     , Peter Mamonov wrote:
> > Signed-off-by: Peter Mamonov <pmamonov@gmail.com>
> > ---
> >  drivers/usb/host/ehci-hcd.c | 6 +++---
> >  1 file changed, 3 insertions(+), 3 deletions(-)
> > 
> > diff --git a/drivers/usb/host/ehci-hcd.c
> > b/drivers/usb/host/ehci-hcd.c index d6df7b8..03d6150 100644
> > --- a/drivers/usb/host/ehci-hcd.c
> > +++ b/drivers/usb/host/ehci-hcd.c
> > @@ -684,7 +684,7 @@ ehci_submit_root(struct usb_device *dev,
> > unsigned long pipe, void *buffer,
> >  				 * root
> >  				 */
> >  				ehci_powerup_fixup(ehci);
> > -				mdelay(50);
> > +				mdelay_non_interruptible(50);
> >  				ehci->portreset |= 1 << port;
> >  				/* terminate the reset */
> >  				ehci_writel(status_reg, reg &
> > ~EHCI_PS_PR); @@ -747,7 +747,7 @@ ehci_submit_root(struct
> > usb_device *dev, unsigned long pipe, void *buffer, goto unknown;
> >  	}
> >  
> > -	mdelay(1);
> > +	mdelay_non_interruptible(1);
> >  	len = min3(srclen, (int)le16_to_cpu(req->length), length);
> >  	if (srcptr != NULL && len > 0)
> >  		memcpy(buffer, srcptr, len);
> > @@ -889,7 +889,7 @@ static int ehci_init(struct usb_host *host)
> >  	ehci_writel(&ehci->hcor->or_configflag, cmd);
> >  	/* unblock posted write */
> >  	cmd = ehci_readl(&ehci->hcor->or_usbcmd);
> > -	mdelay(5);
> > +	mdelay_non_interruptible(5);
> why do you need that much non interruptible delau?

Non-interruptible delays are needed here to prevent ehci_* functions
re-entrance. The re-entrance occurs during a usb bus scan, after
detection of a usb keyboard. As soon as a USB keyboard is detected, it's
driver starts the poller, which interferes with the process of usb bus scan.
However that last one delay may be interruptible.


> >  
> >  	ehci->rootdev = 0;
> >  
> > -- 
> > 2.1.4
> > 
> > 
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> > barebox@lists.infradead.org
> > http://lists.infradead.org/mailman/listinfo/barebox


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