From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6BC56322DC1 for ; Mon, 5 Jan 2026 18:00:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=213.167.242.64 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767636057; cv=none; b=Ywax6mQBZJFVbXT8UfPM2iZ43I2ISCp8bGhFwqOAFKx7z/NpNe076DiBygNqTQUeLvTpJyrmfKmTYfQUDaF8OwziddCA2g6RaUuFj+myGXeVzlvQyJAfI/UsriaARo9/A3LCANvxAPNpl4hVzghEafZXBoHE1exZpKXd+LfVoOc= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767636057; c=relaxed/simple; bh=Efalw4yPnFi6tZ4mGM6uyoosUWtV4UQOt3KF4dgKgNY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Cu9lUaaANMc+rgNOJ3RR+p3SLOOPsom8EQtiax0/IoEYml76VJlinR6UsmbpL5hQRHbA1gAI16grLbMtGTvaMOMPeFrydS+Kxcfq4y2fc/7NXQ1QGpo6IV7z2a4WEIWNvFCBw0VPhXl11GOdBMgsFjuElkAYU26aQMUCKOqZO3I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com; spf=pass smtp.mailfrom=ideasonboard.com; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b=mAvWOkj+; arc=none smtp.client-ip=213.167.242.64 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ideasonboard.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="mAvWOkj+" Received: from pendragon.ideasonboard.com (81-175-209-152.bb.dnainternet.fi [81.175.209.152]) by perceval.ideasonboard.com (Postfix) with UTF8SMTPSA id 2794D14C7; Mon, 5 Jan 2026 19:00:31 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1767636032; bh=Efalw4yPnFi6tZ4mGM6uyoosUWtV4UQOt3KF4dgKgNY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=mAvWOkj+6xl5yUZQQ6y43cGp+BFBjCl6H0BTGS39XgIDYrSBVJGE7WmaKYfWcbSAA wYn7JGZPjJIimIGkBQuQ4Wl6AgqpeWh4rjd6V4p2BpUVqkSSHvpIoNGXEA0LgZdVTS tWmNr59fF3NHpA+t7t6iHcPmRgq9xeq2tTqroFYY= Date: Mon, 5 Jan 2026 20:00:33 +0200 From: Laurent Pinchart To: Ricardo Ribalda Cc: Ralf Jung , Salvatore Bonaccorso , 1121718@bugs.debian.org, Uwe =?utf-8?Q?Kleine-K=C3=B6nig?= , linux-media@vger.kernel.org, regressions@lists.linux.dev, Mauro Carvalho Chehab , Hans de Goede Subject: Re: Bug#1121718: linux-image-6.17.8+deb14-amd64: Logitech C920 HD Pro Webcam shows flickering artifacts (sometimes) Message-ID: <20260105180033.GE10026@pendragon.ideasonboard.com> References: <4rnbopkefvp6h3dwttj4h7cexehqtbuzzz4gatnebdnjzdy2li@bupytpnlk2xh> <2ed13f74-8de3-4caf-8972-26dd5a31e9fc@ralfj.de> <176458169204.346596.13968096833088921213.reportbug@r-ethtop> <0490a39a-28d9-4925-a162-5e4d498be257@ralfj.de> <58a7c628-63dc-48f7-8a46-357ca2d7d500@ralfj.de> Precedence: bulk X-Mailing-List: linux-media@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: On Mon, Jan 05, 2026 at 04:29:24PM +0100, Ricardo Ribalda wrote: > Hi Ralf > > Thanks for the bisect and the report. > > > The patch to remove noprod parameter has been queued for 6.20 :S so we > should look into a more permanent fix soon. > > When you say zoom, do you mean the desktop version of zoom ( > https://zoom.us/download?os=linux ) or the web version > I would assume that it is the zoom app, that is ignoring the "error" > flag from the frames and showing them to the users. Can you confirm > that? Hopefully we can reach zoom and they can fix it. Should we revert the nodrop removal in the meantime ? > Now about the error flag. I have given a fast look at your usb trace > and have only seen 4 frames with "error bits" [1]. Can you add more > tracing? > Do something like: > rmmod uvcvideo > modprobe uvcvideo trace=0xffffffff > > Then start zoom, trigger the error and share the content of your > dmesg. It should contain an explanation of why the driver thinks that > the frames are invalid. > > Thanks! > > [1] I used this filter in wireshark: usb.iso.data[1]!=0x0d && > usb.iso.data[1]!=0x0c && usb.iso.data[1]!=0x0f && > usb.iso.data[1]!=0x0e && usb.addr == "3.34.1" -- Regards, Laurent Pinchart