Hi, > -----Original Message----- > From: Sergei Shtylyov [mailto:sshtylyov@xxxxxxxxxx] > Sent: Thursday, July 26, 2012 5:55 PM > To: Ajay M JAWADE > Cc: linux-usb@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] usb:musb: Fix for Full Speed issue > > Hello. > > On 26-07-2012 10:03, Ajay M JAWADE wrote: > > > After sending the USB Bus reset, Host waits for High Speed Chirps. > > If the soft-disconnect and soft-connect happens during this chirp > > time, then Host doesn't detect this disconnect. > > Why talk about soft-connect when we're already connected (as USB reset > is in progress) and further you talk about disconnect only? > Soft-disconnect and soft-connect is done to prepare the new USB descriptors. As Host was waiting for high speed chirps, it doesn't detect the disconnect and connect. > > Host treats this as Full Speed Device as there are no chirps. > > To avoid this Full Speed Enumeration, soft-disconnect and soft-connect > > should have a 500 mili-second gap when USB cable is connected. > > > Signed-off-by: Ajay Jawade <ajay.jawade@xxxxxxxxxxxxxx> > > Acked-by: srinidhi kasagar <srinidhi.kasagar@xxxxxxxxxxxxxx> > > --- > > drivers/usb/musb/musb_gadget.c | 26 > ++++++++++++++++++++++++++ > > 1 files changed, 26 insertions(+), 0 deletions(-) > > > diff --git a/drivers/usb/musb/musb_gadget.c > > b/drivers/usb/musb/musb_gadget.c index f7194cf..801dbe6 100644 > > --- a/drivers/usb/musb/musb_gadget.c > > +++ b/drivers/usb/musb/musb_gadget.c > [...] > > @@ -1751,6 +1752,31 @@ static int musb_gadget_pullup(struct > usb_gadget *gadget, int is_on) > > /* NOTE: this assumes we are sensing vbus; we'd rather > > * not pullup unless the B-session is active. > > */ > > + > > + /* After sending the USB Bus reset, Host waits for > > + * High Speed Chirps. If the soft-disconnect and soft-connect > > + * happens during this chirp time, then Host doesn't > > + * detect this disconnect. Host treats this as Full Speed > > + * Device as there are no chirps. To avoid this Full Speed > > + * Enumeration, soft-disconnect and soft-connect should have > > + * a 500 mili-second delay when USB cable is connected. > > s/mili-second/millisecond/ > > > + */ > > + > > Empty line not needed here. > > > + if (is_on && (is_on != musb->softconnect)) { > > + > > + /* USB cable presence is decided by reading the VBUS > > + * Level bits of DevCtl register. > > + */ > > + > > Here too. > > > + devctl = musb_readb(musb->mregs, MUSB_DEVCTL); > > + devctl = (devctl & MUSB_DEVCTL_VBUS) >> > MUSB_DEVCTL_VBUS_SHIFT; > > + > > And here too. > > > + if (devctl != 0) { > > + /* USB Cable is connected. Delay the soft-connect */ > > s/connected/powered/? > > > + msleep(500); > > + } > > + } > > + > > WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
