From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=192.198.163.12 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793014708; b=iFNleS6oLvjyJxY6mdWXulXcS1yfILd3w4BlqvWxqaV/HHYmX/6jS62jOolhX1V/Riqu iHxQbQx9T81Jze8PYszkZSz+34t/ZDOe8PmR0YC3N6S1MFPD6Mx012MQPaLsj96SaE/Ks ZI5Kivny2r/76QAe4iIV/COQPXDIZVEzcmtVWhKagJNTq/DHqrAcrbBq/GBnv35EMKd+o 7LfCoPh+ZzPfsJmIAWKxKQQCBJHWyqnj5cawTh6QETNk+940Feixov9oXZ+yK8ZENoAuQ iBFQaa6K5jQ59i6vGQ/HiQ2+WRqApVsjRnhO6Gsbev44lvS95eXRgkjKsmcJQ3QGsYQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793014708; h=DMARC-Filter:DKIM-Signature:X-CSE-ConnectionGUID:X-CSE-MsgGUID: X-IronPort-AV:X-IronPort-AV:Received:X-CSE-ConnectionGUID: X-CSE-MsgGUID:X-ExtLoop1:X-IronPort-AV:Received:Received:Date:From:To: Cc:Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:Content-Transfer-Encoding:In-Reply-To; bh=blxnqThsMk81z4qvMbZ6ri3hXR90Vzov50Fn/Bsuoq8=; b=F9MHAM705dEYTWClLeTRaUVDdqflUaiKOgRdmlo+4P7oqe4mcjC/+0LaKNI+WFi/oHdF HDmcQiewso8fMURUXnweZyjjtmt5XjFbjoGWDpo8EMP2IyaLJNr0gNUVjdq3rvMKQnZSd iYL+ncLuwEtIFnx61S+dhuHUA4XQ6fBST2hoa1oJYt5fl8H9BrXZkXKPel3q60Sw7NlRy np6Y8tnbK9tcFtlHCQaH4f26/57z0PUeuSjC+cTAdmHWclK4DTgQdkze6SuSCkZkzd9Ph NGCtRkX4a3FqpLshJ7YfXuIGq6DXOjpY7OtkNW0BxCrgJRp1YXs91GuwOimVcV+gS2g== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=W7RuWAz2; arc=none smtp.remote-ip=192.198.163.12 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.12]) (using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 9C5C1606A324 for ; Mon, 26 Oct 2026 11:38:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 9C5C1606A324 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 header.s=Intel header.b=W7RuWAz2 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1793014708; x=1824550708; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=LFXbw8h2752XrUusI0960pEZ0NcWauS+1+FZTY+K7jg=; b=W7RuWAz2kfPQyQA5bQMZYIamhY935SQh9tQx97hScfOzMnDsvuZ28RZW RLLiqQZGREadtBBtf13P2lj+3M8aNhxNkFJYnoqJJaEH6fdI32nx1ce4F HBnzS4XnTlbCY02yEW1k+rrVnk+eBdurPwB65pgm72HXvYnQQR+4NMXF7 XbXU7U/ESxeOmanrna631A+fxS1AJR1ola6ssZyRDLMaxbjUC4gLdD4nT iLrNevMchmvjxYvY70bF6xpnLdpdfbLf1jMDORJGqVOL4Sg+tSf5FvdpH WzmpXBWKR+OGydRmaTX1tx9E/a6kfwFAA9CwmqkzgYNyPiAlxDGJ2pX4U Q==; X-CSE-ConnectionGUID: FOr4Yz3cSmK5pED52pnkug== X-CSE-MsgGUID: 8zN88C4JQim/iPrme2T7Cg== X-IronPort-AV: E=McAfee;i="6800,10657,11946"; a="1579586" X-IronPort-AV: E=Sophos;i="6.27,179,1787036400"; d="scan'208";a="1579586" Received: from fmviesa001.fm.intel.com ([10.60.135.141]) by fmvoesa106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2026 04:38:27 -0700 X-CSE-ConnectionGUID: NPEgw9ayQ0qK1DReY3lbYw== X-CSE-MsgGUID: YRb4OqMeTgCl/BOZ9rGSyQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,179,1787036400"; d="scan'208";a="4595198" Received: from black.igk.intel.com ([10.91.253.5]) by fmviesa001.fm.intel.com with ESMTP; 26 Oct 2026 04:38:26 -0700 Received: by black.igk.intel.com (Postfix, from userid 1008) id AA8BE99; Mon, 26 Oct 2026 12:38:24 +0100 (CET) Date: Mon, 26 Oct 2026 12:38:24 +0100 From: Heikki Krogerus To: Ville =?iso-8859-1?Q?Kivel=E4?= Cc: "linux-usb@vger.kernel.org" , "gregkh@linuxfoundation.org" , "acelan.kao@canonical.com" Subject: Re: usb: typec: ucsi: duplicate-altmode filter keeps invalid DP partner VDO on Dell XPS 14 DA14260 Message-ID: References: X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Hi Ville, On Sun, Oct 11, 2026 at 07:34:59PM +0000, Ville Kivelä wrote: > Hi, > > The duplicate partner altmode filter added in 67c92c6419ea ("usb: typec: > ucsi: Detect and skip duplicate altmodes from buggy firmware") keeps the > invalid copy of the DisplayPort partner altmode on this machine and drops > the valid one. The DP altmode driver then cannot bind, and the monitor's > USB hub never works. This is why from now on all quirks for this driver are going to be isolated with either DMI match or something similar. > Hardware: > Dell XPS 14 DA14260 (Intel Panther Lake), BIOS 1.8.2 (2026-05-22) > UCSI over ACPI: \_SB_.UBTC (USBC000:00) > Partner: Dell U2720Q monitor (DP alt mode + USB hub + PD source) > Kernel: 7.2.5 (Arch-based distro kernel "7.2.5-3-omarchy") > > The firmware returns the partner's DP altmode (SVID 0xff01) twice on every > attach: > > ucsi_acpi USBC000:00: con3: Firmware bug: duplicate partner altmode SVID 0xff01 at offset 1, ignoring but please contact the BIOS vendor to fix this issue. > ucsi_acpi USBC000:00: con3: VDO mismatch: 0xff01a043 vs 0x00140045 > > The entry at offset 0 is invalid (0xff01a043: SVID in the upper half, > identical whatever the monitor is configured to). The entry at offset 1 > is the real DP capabilities VDO, and it changes with the monitor's > "USB-C Prioritization" setting, as expected: > > High Resolution: 0x00140045 (UFP_D, receptacle, pin assignments C/E) > High Data Speed: 0x001c0045 (UFP_D, receptacle, pin assignments C/D/E) > > The port exposes a single DP altmode (port2.1, svid ff01, vdo 0x001c1c46), > so the per-SVID cap is 1. The filter keeps the first partner entry and > registers port2-partner.0 with vdo 0xff01a043: > > $ cat /sys/class/typec/port2-partner/port2-partner.0/{svid,vdo,active} > ff01 > 0xff01a043 > yes > > typec_displayport does not bind to it (no displayport/ directory under the > partner altmode), so the OS cannot choose a pin assignment. > > Observed result: > - High Resolution: video works, but the monitor's hub never enumerates, > not even at USB 2.0. > - High Data Speed: the hub (0451:8440) enumerates at SuperSpeed on the > TCSS xHCI and disconnects within ~1 s, as DP mode is entered. USB 2.0 > enumeration starts and never completes. There is no video. > > usb 2-3: new SuperSpeed USB device number 2 using xhci_hcd > usb 2-3: New USB device found, idVendor=0451, idProduct=8440, bcdDevice= 1.10 > hub 2-3:1.0: USB hub found > hub 2-3:1.0: 4 ports detected > usb 3-4: new high-speed USB device number 6 using xhci_hcd > usb 2-3: USB disconnect, device number 2 > ucsi_acpi USBC000:00: con3: Firmware bug: duplicate partner altmode SVID 0xff01 at offset 1, ignoring ... > ucsi_acpi USBC000:00: con3: VDO mismatch: 0xff01a043 vs 0x001c0045 > > The same monitor and cable work fully (video and hub) on a MacBook. > Reproduced on two different USB-C ports, after a full power drain, and > with Dell's "Video/Power only on Type-C ports" BIOS option disabled. > > The root cause is the firmware, and it has been reported to Dell. However, > when duplicates disagree, keeping the first entry is arbitrary. Would it > make sense to prefer an entry that passes basic validation? For SVID 0xff01 > that could mean a non-zero pin assignment field, no reserved bits set, and > the upper 16 bits not equal to the SVID. Alternatively, the driver could > prefer the last entry. I'm happy to test patches. I already send a patch where I disable support for the alternate mode reporting for all Dell XPS systems, but it looks like Greg missed that patch - I'll resend it: https://lore.kernel.org/linux-usb/20260911132850.1580669-1-heikki.krogerus@linux.intel.com/ It does not make sense to attempt to add more and more quirks to this driver that fix firmware problems on these systems. Dell really has to fix the PPM. > Also seen once at boot on the same machine (cleared by reloading ucsi_acpi): > > ucsi_acpi USBC000:00: con1: failed to register alt modes > ucsi_acpi USBC000:00: error -ETIMEDOUT: PPM init failed That should get fixed with the above patch as well. Thanks, -- heikki