From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=192.198.163.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793787983; b=qOpY8g/UT61LCBDTHNoOgYH3CsBsFD0s/nhWYe3ioOZ3kW1iqPsNbPV5ydAhDDrMsBjC d30cTbfkIY0LeuCgt7o3F9vqbboFyGERJjnMD/ZxdhcY4ICXT134pui4K2ThYvRHmU438 6qEnP3i+tHEnD0TIDLkwK5DhCemAs0WvEJ5Elxju6hXizy8PYiH6/9u3COrgd+YBMjyHh kkz4t5ljSoItyCAgJLwWpoXHBV7vxag740FHGS32CuXHTWYjIRzthZKl0FyHH2Igelsid iIS8zsdOnfKMVrKljMt9/YOhZGXsF+NvDsxLWCDy/q7UXqjBl5E9QIaeoqKT1zpQb8Q== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793787983; 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=Va8WcfmPKt8pnEE/84ALLfThwAWUQvCummgZ7+O/2eU=; b=AYlBcqwnDn91B6fVLr85fejNbOzmnqK6dSwPT8L8ngCLEUkDdpVVTaRO/NZiOMRFM95M iJgH2fW6xaYsxFJVqvh6gqzHstE5dia84mB927rrznTJQ4p4/VwnSCWF6WmISTgYoii84 2odBNRzfuEA/bAe631c9Op8UM30OFY1b8TGgiTwhO93ah3TneacHfb1o8wM6plcK/xy7C MdWLw0cHyPNZrSZnYCAM7VXlG4744UhUTV3RvWcGOTK1mCXWTd/MsZfbRYSRGKpjSKKmg sN/6ADvva45PZSeqW/rESHCfecPQl485Elw1fg1EXfaukBSkqwUJ4Rv0Xr7C1NltxUw== 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=njYXusLE; arc=none smtp.remote-ip=192.198.163.18 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.18]) (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 D93E5606A328 for ; Wed, 4 Nov 2026 10:26:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org D93E5606A328 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=njYXusLE DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1793787983; x=1825323983; h=date:from:to:cc:subject:message-id:references: mime-version:content-transfer-encoding:in-reply-to; bh=c4RVmcwFoz2DEclj9/DTujKMxc2+REOPArEukpzgjrc=; b=njYXusLEzRHM5qE3FV0YLgbNosWeyqYdxHBpG3jrIUABr+UUTSpaGGdA mTre39Jwa7nd8Ivkpe90e4d5voBqOfjtwSyWpji3E08DD++dvoCTgWJYU gv13ZWk8xoHuXFHWY13L2HLq84LkcFEoSJLOqD0/ZH9d7U/I0ZAEP7kPW 64Zfl2hNqPgZMBy7QaQ24oFpEFxd5JzYFkFk7QrbQKXGpFauXjYUm9AR3 votrKuegs0hN/gYp+4NHslmkCQ86G1kw5rNIPP0NNixaRxCewGnQRl4hL tZnDOgmG8KZpoITyJ6UspsNghFlrgCgquJWsL5xfe9Rp+1x7g8igsiCby g==; X-CSE-ConnectionGUID: Gx2FRyk0T2Oe7QQ/s430kg== X-CSE-MsgGUID: lTz6G+w1S8iCV1YeIzm6XA== X-IronPort-AV: E=McAfee;i="6800,10657,11955"; a="2571958" X-IronPort-AV: E=Sophos;i="6.27,195,1787036400"; d="scan'208";a="2571958" Received: from orviesa009.jf.intel.com ([10.64.159.149]) by fmvoesa112.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 04 Nov 2026 02:26:22 -0800 X-CSE-ConnectionGUID: 1PE0ZeNMSV+J0BSDMpwVxg== X-CSE-MsgGUID: yVrEcShdSsi4moS1flYlyA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.27,195,1787036400"; d="scan'208";a="6786740" Received: from black.igk.intel.com ([10.91.253.5]) by orviesa009.jf.intel.com with ESMTP; 04 Nov 2026 02:26:21 -0800 Received: by black.igk.intel.com (Postfix, from userid 1008) id AEB1F99; Wed, 04 Nov 2026 11:26:19 +0100 (CET) Date: Wed, 4 Nov 2026 11:26:19 +0100 From: Heikki Krogerus To: Rodolfo Semprevivo Cc: linux-usb@vger.kernel.org, mathias.nyman@linux.intel.com, intel-xe@lists.freedesktop.org Subject: Re: Panther Lake UCSI: PPM =?utf-8?Q?force?= =?utf-8?Q?s_DP_alt_mode_pin_assignment_D_=282_lanes=29_for_C=2FE-only_par?= =?utf-8?Q?tner=2C_no_4K60_=28was=3A_=5BBUG=5D_Type-C_Subsystem_xHCI_=2880?= =?utf-8?Q?86=3Ae331=2C_Panther_Lake=29_=E2=80=94_repeate?= =?utf-8?Q?d?= err -71 / port reset failures under sustained DP+HID load) Message-ID: References: <91bd4409-8121-4919-8556-8b49ec8f9304@semprevivo.ch> 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: <91bd4409-8121-4919-8556-8b49ec8f9304@semprevivo.ch> On Fri, Oct 23, 2026 at 10:27:32PM +0200, Rodolfo Semprevivo wrote: > Hi, > > follow-up to my report below, with a corrected analysis. The xHCI was > the wrong suspect: the -71 errors come from the monitor's internal USB > 2.0 hub, which sits on the standalone xHCI (8086:e37d, 00:14.0), not on > 8086:e331. They only appear because the monitor resets when the DP link > fails. > > Root cause: on the left TB4 port the PPM/EC configures DP alt mode with > pin assignment D (2 lanes), although the monitor only advertises C and E: > >   port0-partner.0: svid ff01, active yes, vdo 0x00140045 >   displayport/pin_assignment: C E   (nothing selected) >   displayport/configuration: [USB] sink >   xe: Port D/TC#1: TC port mode reset (disconnected -> dp-alt) pin > assignment: D max lanes: 2 >   xe: [LTTPR 1] Link Training passed at link rate = 540000, lane count = 2 > > 2x HBR2 is not enough for 3840x2160@60 (594 MHz), so the picture drops > regardless of bpc/HDR. Lower resolutions at 60 Hz work. This also > explains why the dGPU route via the MUX failed identically: the lane > split is decided by the firmware, not by the GPU driver. > > For comparison, an Alder Lake ASUS GU603ZW on the same kernel, with the > same monitor and cable: > >   i915: Port D/TC#1: ... pin assignment: C max lanes: 4 >   i915: Link Training passed at link rate = 540000, lane count = 4 > > and 4K60 is stable. > > Linux cannot correct this. Writes to pin_assignment/configuration fail > with EOPNOTSUPP: > >   typec_displayport port0-partner.0: firmware doesn't support alternate mode > overriding >   ucsi_acpi USBC000:00: UCSI_GET_PDOS failed (-95) > > So this looks like a firmware issue (reported to ASUS as well). > Questions: > 1. Is the PPM choosing pin assignment D for a partner that does not >    advertise D a known issue on Panther Lake? I have not heard of this particular problem before. > 2. Should Linux warn about it (partner VDO lacks D but FIA reports D), >    or avoid the resulting 2-lane DSC mode? You tell me. If you think that this would be useful, prepare the patch for it. > System: ASUS ROG Zephyrus G16 GU606AX (Panther Lake, Core Ultra 9 386H), > BIOS GU606AX.304, kernel 7.3.0-4 (CachyOS), monitor ASUS ProArt > PA169CDV. Bug report: https://paste.cachyos.org/p/83e1bcf.log > Full drm.debug log available on request. Thanks, -- heikki