From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 E927A5CDF1 for ; Sun, 28 Dec 2025 13:18:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766927885; cv=none; b=jy9JMJ+ZkkXsmnTiiBhMuFFuxli0sLQ+8B4ieFzmKL9olRAFhHoKHOgJfyp/Ss28RyvCrjsZQ05Z/Rt3n+4Me93FKD9/zyN014Gg2XFhLYcY/b/T/Cn2BV8O55gJ5E/cqUC8vwSOs0I18hsJEyrmdjBmzM0lT4lJSFcz7rkqxCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766927885; c=relaxed/simple; bh=jatR+YU310OmSeoIzp2G5Iu/V9w/Q0meZGofURdi/oY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=lU//lhQwqcUjOnRvkwsbIhfUfvWeBGmlE9ZYZI0MSxnHHbNTMiVmLZab7cLwkQ6DIvabwuSq9Vwxu3e+xVWQI6wekwtWKM75yzCqGTjBVdkUywBLwoddfZXUV1/cXsQPdKIJcgIBXgtU+6lFVVXRp/9jnoLbpBIGFmbv6UV9Zxw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=zc8lD/Nk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="zc8lD/Nk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id ED563C4CEFB; Sun, 28 Dec 2025 13:18:03 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1766927884; bh=jatR+YU310OmSeoIzp2G5Iu/V9w/Q0meZGofURdi/oY=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zc8lD/NkdrNQ0jadZ9iQei+KsiwF7NiKlbapZsLV60rmx8HeH7MEu0z2seIsERHE9 9f7aOhU2lN+IRfkHtDIDfxdcZ1uVpvYSdvygkx/loIjPQQj3S5H3Sw/LwQ2wNaR0WP bGnnN1gUfMNmga8oYPnn4xX2Pn0jJ1tr9aXFSLhU= Date: Sun, 28 Dec 2025 14:18:01 +0100 From: Greg KH To: Johannes =?iso-8859-1?Q?Br=FCderl?= Cc: Oliver Neukum , Michal Pecio , linux-usb@vger.kernel.org Subject: Re: [PATCH v2] usb: core: add USB_QUIRK_NO_BOS for devices that hang on BOS descriptor Message-ID: <2025122837-creamlike-motivator-8dcb@gregkh> References: <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> <2025120941-unhappily-smilingly-59e9@gregkh> 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=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: On Sun, Dec 28, 2025 at 01:54:34PM +0100, Johannes Brüderl wrote: > On Mon, Dec 8, 2025 at 9:46 PM Greg KH wrote: > > > > On Mon, Dec 08, 2025 at 09:58:55AM +0100, Oliver Neukum wrote: > > > On 07.12.25 22:12, 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. > > > > > > 1. That means we'd let lsusb crash devices. Not a good idea. > > > > I don't think that it will crash. hopefully not, as just reading a > > descriptor after enumerated shouldn't cause that. I'll test it out... > > > > > 2. It is, unfortunately, possible that firmware authors simply > > > script a detection sequence. That means devices would crash > > > if you request a descriptor at a time when Windows would not > > > request it, not just in general. > > > I am afraid I need to point you at the horrible example > > > of HID_ALWAYS_POLL > > > > That is horrible, hopefully we don't have to do that here :( > > > > thanks, > > > > greg k-h > > Hello Greg, > I apologize for the "blunt bump" of this topic. > Are you (still) open to considering the quirk ? > > A small number of users have started using the Patch, and it seems to > solve a real problem.. (ref: > https://www.reddit.com/r/elgato/comments/1lw1e0v/comment/ntrdjpb/?utm_source=share&utm_medium=web3x&utm_name=web3xcss&utm_term=1&utm_content=share_button) > > Given that the options for 4k60fps recording are very limited for > Linux these days - I suggest it might be worth it. AFAIK, there's no > good other option in terms of hardware as of December 2025. > I understand it's a special quirk for just this device, which is not pretty.. > > (Note: i've submitted a v3 patch that addressed the feedback). Sorry, I haven't had a chance to dig into this due to travel and the holidays. Give me a few days to catch up... thanks, greg k-h