From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E305C4183AE for ; Fri, 5 Jun 2026 15:03:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780671799; cv=none; b=FssISuvR0J/xQG7fJrAkj0sDXDQf5RjVWr8R0Bu/+wtERl4u/f7OZJPMZGqDmkjHcYec+m2R0FDjasdkUx7atFCc1ol+0410v2EpquIR7JyI3VXNZaTaLBLCgVQ1fkNNpGcc3hNWvh9U0AdLC6HxmU548ROzzFzK29wCH6NCccU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780671799; c=relaxed/simple; bh=G6x+e0pDg3YCGAERnb0DFO5RZkClItCyLerDFW18aNc=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TZLFsKXycLFrOr1wTkz9MSxs5mImnYQ6g4sGZbN9SHQmanY1LFxGs1IJ8Sf/PzRxUKiJcDAQlGMb+2rtHQlCxl5sDB8BJ7I5uzjX59m8iHHo+dv+ur0jIee1fJ/QJoTzsjTAKSCamRyz/SDUixHm9iQ2WbNMc92bAviG3WFzTIE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=umQvZtnf; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="umQvZtnf" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 47EBB1F00893; Fri, 5 Jun 2026 15:03:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1780671798; bh=YcSL9VIpTAV4A74fdsdcI/OQgAJoq3zsED7IbZORToY=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=umQvZtnfe+L1KQwi28A5jOOaZLAxa8IgdWIzR6C+nxsQHh20Qn+9J8n/Nar9ckbyA 4f3/eMnlEKn/7gQGZRNDet9rojwnrNt7y7ZI/4oMK3Fu3x2DQ2hiPcsI2nHeku1syt Mkg5ePcfwBHKxFt6GaxuTAIVcNOqdme9QMk6OKzY= Date: Fri, 5 Jun 2026 08:15:25 +0200 From: Greg KH To: Michal Pecio Cc: Johannes =?iso-8859-1?Q?Br=FCderl?= , linux-usb@vger.kernel.org, A1RM4X , Vyacheslav Vahnenko Subject: Re: [PATCH v2] usb: core: add USB_QUIRK_NO_BOS for devices that hang on BOS descriptor Message-ID: <2026060544-roundup-mobster-8fcd@gregkh> References: <2025120708-header-startling-ffaf@gregkh> <20251207012059.7899-1-johannes.bruederl@gmail.com> <20251207084012.7c232e52.michal.pecio@gmail.com> <20251207104505.1d5f3718.michal.pecio@gmail.com> <2025120748-extras-retrain-16eb@gregkh> <2025120846-nearby-breath-e5fe@gregkh> <20260604165619.592c4e24.michal.pecio@gmail.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260604165619.592c4e24.michal.pecio@gmail.com> On Thu, Jun 04, 2026 at 04:56:19PM +0200, Michal Pecio wrote: > On Mon, 8 Dec 2025 06:12:15 +0900, Greg KH wrote: > > Ok, I can duplicate this here. Maybe we just don't ask for the BOS > > descriptor if no one needs/asks for it. I can play with that later > > and see if that helps as I'm sure this isn't going to be the only > > device that can't handle the BOS descriptor if Windows isn't querying > > for it, so we don't want to make a huge quirk table if we don't have > > to. > > Hi Greg and others, > > The workaround is now in, but if somebody is interested in getting rid > of it, it might suffice to make kernel BOS requests more Windows-like, > since these devices work fine with Windows (and Windows queries BOS). > > By monitoring Windows 10 in a VM I found two key differences: Windows > fetches BOS *after* the configuration descriptor, and it requests 255 > bytes at once in its first attempt (there is likely a second attempt > if BOS length exceeds 255, but I don't have such a device to test). > > Any chance that the change below is enough for these video grabbers? Have you tried it? I'm away from my device for a few more weeks and can't do it myself. thanks, greg k-h