From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 24 Jan 2002 22:29:17 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 24 Jan 2002 22:29:08 -0500 Received: from charger.oldcity.dca.net ([207.245.82.76]:20973 "EHLO charger.oldcity.dca.net") by vger.kernel.org with ESMTP id ; Thu, 24 Jan 2002 22:29:04 -0500 Date: Thu, 24 Jan 2002 22:28:57 -0500 From: christophe =?iso-8859-15?Q?barb=E9?= To: lkml Subject: usb or video4linux problem Message-ID: <20020125032857.GA671@online.fr> Mail-Followup-To: lkml Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="UugvWAfsgieZRqgk" Content-Disposition: inline User-Agent: Mutt/1.3.26i X-Operating-System: debian SID Gnu/Linux 2.4.17 on i586 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org --UugvWAfsgieZRqgk Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable I send a mail few days ago about a problem with a usb webcam (Dlink DCS100). I see the same thing with various webcam apps (gnomemeeting, gqcam, camstream, xawtv, ...). So clearly it's not a user-level problem. It can be a hardware one but i'm convinced it is not (or in the OHCI chip in my toshiba satellite 2520cds). With all app I can see the stream but suddenly it freezes. Because of the following output from xawtv when the problem occurs: v4l: timeout (got SIGALRM), hardware/driver problems? ioctl: VIDIOCSYNC(0): Appel syst=E8me interrompu I have checked out the code and the interesting part in drv1-v4l.c is : alarms=3D0; alarm(SYNC_TIMEOUT); retry: if (-1 =3D=3D (rc =3D xioctl(h->fd,VIDIOCSYNC,h->buf_v4l+frame))) { if (errno =3D=3D EINTR && !alarms) goto retry; } =46rom which I conclude that SYNC_TIMEOUT could be to small. The value is 3 secondes which seems to be quite enough. To be sure I've tried with 30 and got the same thing. So It's a justified timeout because the nextframe will never be there. usbview sees the webcam before and after the problem. Restarting the app is enough to get the stream.=20 I'm convinced that it's a problem with OHCI. I think it's a soft problem because I can trigger it with cpu/io activity. What can I do to go further ? Christophe --=20 Christophe Barb=E9 GnuPG FingerPrint: E0F6 FADF 2A5C F072 6AF8 F67A 8F45 2F1E D72C B41E People that hate cats will come back as mice in their next life. --Faith Resnick --UugvWAfsgieZRqgk Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.6 (GNU/Linux) Comment: Pour information voir http://www.gnupg.org iD8DBQE8UND5j0UvHtcstB4RAjRgAJ4qZ6pHU+AQ1XEdRRLKPrGfyp+H0gCcD27e 2gXotpF477uUZqexSCV48KQ= =cawO -----END PGP SIGNATURE----- --UugvWAfsgieZRqgk--