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 32A4F41DDE8; Sun, 6 Sep 2026 08:50:47 +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=1788684650; cv=none; b=NNSk8ToMiLSMx9cbwsXi/AqQw5u6vp2LYk3DeW5f6ocQfvTo9tmZOoPC54/V+pxyDybcFfn8nzLxl2mwsBNDy8JTP2FWrj6uWyVoZYeWPSwptAvbTrKG6y8wFJYH+HTQ5TAZOVxBJxPH+8ERQGhBTxsDScMi0em4lQ7/MUWUpOg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788684650; c=relaxed/simple; bh=QCrxkLnBheZdSWs0VdpLCLOhV0iO414xVZBbiQbr2TY=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j6KR+o4JGA+G+JBq2bpEbrxpNfBG10f2wsYNHNfcLCURUq9LJ3FmfnDXemucJBu+Npa62T+e51xchoDBjSCrLCG0UnRoxTpZzVRNEaeBAC/iXPJ/pbHxRlGCIgSZqA8iwDPmZhOjPXFED1D1X4Vr82lWEs7s4ivxSHpmstbFtiU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=kdnF7prQ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="kdnF7prQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 25BE01F00A3A; Sun, 6 Sep 2026 08:50:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788684646; bh=0id2YY5pP9gAEYb7cM3kFahfETFF3hnWLbjOK24RpHQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=kdnF7prQ8zopDeyyKcLUegLUsYl9i/7Z0B0Z/bFghhmV2Jtbyj/E4IJ5P9UZoO3nW M0lbYNeiprBfoX28//ylZBcpaKgCdPGNPS7C2oIIhVyLZ+xc+4i3d2U7Elq6yNwrHz WVWPW8lcqnb3KQ1Dq6O85vLPElvFEESM5B3MQ/pL6v9FunfVyV/dTrl36bjM2WVQfB ytYSuFMijPSQytIBk1NKRhjIwiIKvDxf4NeoSnRx2v8OEYx0MzzD+RZ1BWr/ERUtnb nQrf7sI2xxpcvV+cOgE6I/Bds8OEyVOAyCih/qreUR6iejI/3bcJrtrtU8ROWl+DvN 5+n08F2mZa/0w== Date: Sun, 6 Sep 2026 09:50:42 +0100 From: Simon Horman To: "Rawda, Tony" Cc: "anthony.l.nguyen@intel.com" , "przemyslaw.kitszel@intel.com" , "intel-wired-lan@lists.osuosl.org" , "netdev@vger.kernel.org" , "linux-kernel@vger.kernel.org" , "richardcochran@gmail.com" , "vitaly.lifshits@intel.com" , "sasha.neftin@intel.com" Subject: Re: [PATCH] e1000e: set fixed clock frequency indication for Alder Point Message-ID: <20260906085042.GF40544@horms.kernel.org> References: Precedence: bulk X-Mailing-List: linux-kernel@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: On Thu, Sep 03, 2026 at 06:06:33PM +0000, Rawda, Tony wrote: > On some Alder Point (e1000_pch_adp) platforms the XTAL value reported in > the software STRAP is incorrect, so the SYSCFI bit in TSYNCRXCTL selects > a 24 MHz base frequency while the SYSTIM counter actually advances at > 38.4 MHz. As a result the PTP hardware clock runs ~1.6x too fast > (38.4/24), which prevents ptp4l and other PTP-based time sync from > disciplining the clock. > > Commit 688a0d61b2d7 ("e1000e: set fixed clock frequency indication for > Nahum 11 and Nahum 13") fixed the same problem for e1000_pch_mtp, > e1000_pch_lnp and e1000_pch_ptp. Alder Point silicon likewise always > runs at 38.4 MHz, so give it the same fixed-frequency override in both > e1000e_get_base_timinca() and e1000e_ptp_init(). > > Observed on an HP Z2 Mini G9 with I219-LM (17) [8086:1a1c]: before the > change the PHC advanced 16.0 s per 10.0 s of wall-clock time and > /sys/class/ptp/ptpN/max_adjustment read 999999999 (MAX_PPB_24MHZ); > afterwards it advances ~10.0 s and max_adjustment reads 230769100 > (MAX_PPB_38400KHZ). > > Fixes: 59e466888038 ("e1000e: Add support for Alder Lake") > Cc: stable@vger.kernel.org > Signed-off-by: Tony Rawda Reviewed-by: Simon Horman