Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753596AbcD0Jd7 (ORCPT ); Wed, 27 Apr 2016 05:33:59 -0400 Received: from mga02.intel.com ([134.134.136.20]:23507 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753069AbcD0Jdz (ORCPT ); Wed, 27 Apr 2016 05:33:55 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.24,540,1455004800"; d="asc'?scan'208";a="793352705" From: Felipe Balbi To: changbin.du@intel.com Cc: gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, "Du\, Changbin" , Du@vger.kernel.org Subject: Re: [PATCH] usb: dwc3: usb/dwc3: fake dissconnect event when turn off pullup In-Reply-To: <1461745745-3954-1-git-send-email-changbin.du@intel.com> References: <1461745745-3954-1-git-send-email-changbin.du@intel.com> User-Agent: Notmuch/0.21+96~g9bbc54b (http://notmuchmail.org) Emacs/25.0.90.3 (x86_64-pc-linux-gnu) Date: Wed, 27 Apr 2016 12:31:49 +0300 Message-ID: <87wpnjmm7u.fsf@intel.com> MIME-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha1; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4428 Lines: 132 --=-=-= Content-Type: text/plain Content-Transfer-Encoding: quoted-printable Hi, changbin.du@intel.com writes: > From: "Du, Changbin" > > The dwc3 controller can't generate a disconnect event after it is > stopped. Thus gadget dissconnect callback is not invoked when do not generating disconnect IRQ after you drop Run/Stop is expected. > soft dissconnect. Call dissconnect here to workaround this issue. I'm rather sure this is a bug elsewhere. How do you trigger this ? > Note, most time we still see disconnect be called that because > it is invoked by dwc3_gadget_reset_interrupt(). But if we > disconnect cable once pullup disabled quickly, issue can be > observed. I can't understand what you're trying to say with this. > Signed-off-by: Du, Changbin > --- > drivers/usb/dwc3/gadget.c | 33 ++++++++++++++++++++++++--------- > 1 file changed, 24 insertions(+), 9 deletions(-) > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > index 8e4a1b1..cd73187 100644 > --- a/drivers/usb/dwc3/gadget.c > +++ b/drivers/usb/dwc3/gadget.c > @@ -1566,6 +1566,15 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, = int is_on, int suspend) > return 0; > } >=20=20 > +static void dwc3_disconnect_gadget(struct dwc3 *dwc) > +{ > + if (dwc->gadget_driver && dwc->gadget_driver->disconnect) { > + spin_unlock(&dwc->lock); > + dwc->gadget_driver->disconnect(&dwc->gadget); > + spin_lock(&dwc->lock); > + } > +} > + > static int dwc3_gadget_pullup(struct usb_gadget *g, int is_on) > { > struct dwc3 *dwc =3D gadget_to_dwc(g); > @@ -1575,6 +1584,21 @@ static int dwc3_gadget_pullup(struct usb_gadget *g= , int is_on) > is_on =3D !!is_on; >=20=20 > spin_lock_irqsave(&dwc->lock, flags); > + /** > + * WORKAROUND: The dwc3 controller can't generate a disconnect > + * event after it is stopped. Thus gadget dissconnect callback > + * is not invoked when do soft dissconnect. Call dissconnect > + * here to workaround this issue. > + * Note, most time we still see disconnect be called that because > + * it is invoked by dwc3_gadget_reset_interrupt(). But if we > + * disconnect cable once pullup disabled quickly, issue can be > + * observed. > + */ > + if (!is_on && (dwc->gadget.speed !=3D USB_SPEED_UNKNOWN)) { > + dev_dbg(dwc->dev, "fake dissconnect event on pullup off\n"); > + dwc3_disconnect_gadget(dwc); > + dwc->gadget.speed =3D USB_SPEED_UNKNOWN; > + } this is *really* wrong. You shouldn't be calling pullup directly. This patch looks wrong and you didn't even explain how to trigger this problem; when does the problem happen ? Gadget load/unload does the right thing here, so that can't be the case. We also do the right thing on soft_connect sysfs file: static ssize_t usb_udc_softconn_store(struct device *dev, struct device_attribute *attr, const char *buf, size_t n) { struct usb_udc *udc =3D container_of(dev, struct usb_udc, dev); if (!udc->driver) { dev_err(dev, "soft-connect without a gadget driver\n"); return -EOPNOTSUPP; } if (sysfs_streq(buf, "connect")) { usb_gadget_udc_start(udc); usb_gadget_connect(udc->gadget); } else if (sysfs_streq(buf, "disconnect")) { usb_gadget_disconnect(udc->gadget); udc->driver->disconnect(udc->gadget); usb_gadget_udc_stop(udc); } else { dev_err(dev, "unsupported command '%s'\n", buf); return -EINVAL; } return n; } static DEVICE_ATTR(soft_connect, S_IWUSR, NULL, usb_udc_softconn_store); So really, what _is_ the problem ? =2D-=20 balbi --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJXIIcFAAoJEIaOsuA1yqRE7bEP/joB6zXWFg8jWUPRz0hZNOYK mscGd+zkpK+7NR+KdzpFlNTVln96qWnf07UwWZQhlaf9woHmZidA6YDJe/VeRDRV dV2+9e/6eKTfUHr83NURn50hwYL8GJinKbzr63Ju3x+0QGZEPM+dQ5sj6DIaBvrx OiImk9RjyHzNZSjYVvR6XrGyJuXbUkoWZey1bBCSYWCmankYFHuqf3CIsQ4cHRUX tB+JH7jRbunUz/DpAFohoyuCVs4AnUsp9vQNAelMhspxwNlUCcnxWPELrO1nbq2Y VaEKtJrWJTIIvVp2wCRnwVcx43v5sDw5vSgfh/kt/c4WhqavzMwOCCaVAfPKo3V6 p+H7miTBG04tW4TDoGDyvEudacqx4mH50pZBkHYSQ5z6HqdhrDdNgWY1yNrXiJI6 1sIbzG1FWONid5r9x2+qbA1wDVaWuJ56YWm/IolEvSzJnH0s0AQq5Kwy0jGpTCfT jmhjEtXxcRdCk83NSZiUn+WqyI3tXEM00qvf47kTGwUK+gM2/cRcuUlsDDQRvXcM CPTuZMhHDkdS0TgBjrntEI2cd+ou5P/HvUEoihAY1pd8LNtEiQUpKYnKj0PhbW9b zZPoTEwZbmGBzaNAaJgEfodOShWp65ODXNmqnfcdj8ryYtx3q+Kv90sNZyLo+Sy/ zuO51meRafrgO0yZTfcH =+Mue -----END PGP SIGNATURE----- --=-=-=--