From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) (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 3C34E3F7891; Tue, 2 Jun 2026 17:15:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=90.155.50.34 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780420540; cv=none; b=NzIsJ6Uiq7brsVW315ZSXBg4gzuv3shaSb6XkZ9vMI2Iie345gVw7tqt25Pm2qhuffnco0V2fLYLEENyxd3XRjV8dAoqZnGXseFehBpfy7B43PiKB38EtcgnPSwNEimd/VP14xdLg/zweONXUsWsUMUrCwvX1nAuYkPUpaFE6P4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1780420540; c=relaxed/simple; bh=kkyXPebYwJ/UpauPaOt24fg6+WUOD4Y08/xBiZarvsY=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=n6lDQeDpF51/cL/UfrUot+mbHaIQim0kt38esH0rEKFx9Iyc/x4HlMv/d7t8Cq0W6Ruf1a2LtIIvgjRs0j85+Mow2EH96cq6mOzxCrxwzCnuMug3Ryqgs1J7bKxzv02tagPMU0qLaVoevSoP6NiXwdkklXGlb9jMuk3+NAKvxqI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=casper.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=lGAMQcp1; arc=none smtp.client-ip=90.155.50.34 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=casper.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="lGAMQcp1" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=MIME-Version:Content-Type:References: In-Reply-To:Date:Cc:To:From:Subject:Message-ID:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=kkyXPebYwJ/UpauPaOt24fg6+WUOD4Y08/xBiZarvsY=; b=lGAMQcp1U6l4eDLhRrdmc+i+hK +ykaJocmPqWV//dQk9GAoty1ZemGnXbTg16FLKBPlb155JpUD1l6wAniJ7Ozjc255EnI/cgQgNpDv UjUUTmEEac9PmqABeWHGcK9SFBPqgO7GlqmtqYpNTlh1ZprBIHAhL9DRemdKL19Olpdvs/WOmre/7 WoH23nY0KAaQKL0I3bVkZ+9AvdfUBxb833nUrEQnr1ZsNXXIo+rvEiL8bvNx7b6QcTZqxl/P6Qz2r Vgpgyn6PVj8hWYwDZrQljmiqqE5Eu2EhT/z4KoKBKJZsZxvAuFrc1DQ0twHmEm3I/7UopLyC5ub18 xdHfrh7A==; Received: from [2001:8b0:10b:5:c68:987:fac8:ab00] (helo=u09cd745991455d.ant.amazon.com) by casper.infradead.org with esmtpsa (Exim 4.99.1 #2 (Red Hat Linux)) id 1wUSi7-00000002KiL-3HEV; Tue, 02 Jun 2026 17:15:28 +0000 Message-ID: <27ff3ab8ea24a80812c54d18a18bda65acce5c08.camel@infradead.org> Subject: Re: [PATCH v2 2/2] MAINTAINERS: update PTP maintainer entries after directory split From: David Woodhouse To: Wen Gu , Richard Cochran , Jakub Kicinski Cc: tglx@kernel.org, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org, jstultz@google.com, anna-maria@linutronix.de, frederic@kernel.org, daniel.lezcano@kernel.org, sboyd@kernel.org, vladimir.oltean@nxp.com, wei.fang@nxp.com, xiaoning.wang@nxp.com, jonathan.lemon@gmail.com, vadim.fedorenko@linux.dev, yangbo.lu@nxp.com, svens@linux.ibm.com, nick.shi@broadcom.com, ajay.kaher@broadcom.com, alexey.makhalov@broadcom.com, bcm-kernel-feedback-list@broadcom.com, linux-fpga@vger.kernel.org, imx@lists.linux.dev, linux-s390@vger.kernel.org, dust.li@linux.alibaba.com, xuanzhuo@linux.alibaba.com, mani@kernel.org, imran.shaik@oss.qualcomm.com, taniya.das@oss.qualcomm.com Date: Tue, 02 Jun 2026 18:15:27 +0100 In-Reply-To: <335ae01a-20aa-439e-996c-d35ffd8d476a@linux.alibaba.com> References: <20260412084704.743482ad@kernel.org> <4B889ED5-D1F6-401D-B753-89AE2037F316@infradead.org> <20260412095301.4fe1fe65@kernel.org> <1088b07d760491deb461d6d01abca631e8f8d86c.camel@infradead.org> <3908843460c4864eef79cced40d897f793c7ae2a.camel@infradead.org> <0e023f951c102fe2ee7070e490c579783b2817d5.camel@infradead.org> <20260601185226.7f43fa75@kernel.org> <0b3f00bbfa6bcc3badb4d1bb7845326e2dbaa1d4.camel@infradead.org> <335ae01a-20aa-439e-996c-d35ffd8d476a@linux.alibaba.com> Content-Type: multipart/signed; micalg="sha-256"; protocol="application/pkcs7-signature"; boundary="=-bFbDCAYFbExy0zXwkgt3" User-Agent: Evolution 3.52.3-0ubuntu1.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html --=-bFbDCAYFbExy0zXwkgt3 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable On Tue, 2026-06-02 at 22:03 +0800, Wen Gu wrote: >=20 > > There is some extra stuff we want to do for "Precision RTCs" or > > whatever we're going to call them. They might actually have a known TAI > > offset, they might convey leap second indications, we might want to set > > the kernel's CLOCK_REALTIME from them at boot. And in the case of > > VMClock, I'm working on being able to clamp the kernel's timekeeping to > > it directly=C2=B2. > >=20 > > So maybe what we want is linux/drivers/phc, to host those read-only > > devices which know real time. They can provide a simplified > > implementation; maybe *only* a function like vmclock_get_crosststamp(), > > which is just called in various different permutations by the various > > different PTP methods. > >=20 > > The core linux/drivers/phc code would then handle the interface to the > > kernel's core timekeeping *and* wrap them to register a PTP device that > > existing userspace can understand. And deal with the kvmclock/TSC > > awfulness where needed. > >=20 > > How does that sound? > >=20 >=20 > I think a dedicated phc core would make the classification of read-only > clocks clearer, reducing ambiguity around where they belong. I assume > direct timekeeping integration would be optional, drivers providing > only a snapshot-based crosststamp would use /dev/ptpX alone, while the > timekeeping path would require additional capability (as vmclock provides= )? Yeah. I think they might all want to be able to opt in to setting the time at boot? But actually setting the fine-tuning of the kernel's timekeeper is probably only something vmclock can do. --=-bFbDCAYFbExy0zXwkgt3 Content-Type: application/pkcs7-signature; name="smime.p7s" Content-Disposition: attachment; filename="smime.p7s" Content-Transfer-Encoding: base64 MIAGCSqGSIb3DQEHAqCAMIACAQExDzANBglghkgBZQMEAgEFADCABgkqhkiG9w0BBwEAAKCCD9Aw ggSOMIIDdqADAgECAhAOmiw0ECVD4cWj5DqVrT9PMA0GCSqGSIb3DQEBCwUAMGUxCzAJBgNVBAYT AlVTMRUwEwYDVQQKEwxEaWdpQ2VydCBJbmMxGTAXBgNVBAsTEHd3dy5kaWdpY2VydC5jb20xJDAi BgNVBAMTG0RpZ2lDZXJ0IEFzc3VyZWQgSUQgUm9vdCBDQTAeFw0yNDAxMzAwMDAwMDBaFw0zMTEx MDkyMzU5NTlaMEExCzAJBgNVBAYTAkFVMRAwDgYDVQQKEwdWZXJva2V5MSAwHgYDVQQDExdWZXJv a2V5IFNlY3VyZSBFbWFpbCBHMjCCASIwDQYJKoZIhvcNAQEBBQADggEPADCCAQoCggEBAMjvgLKj jfhCFqxYyRiW8g3cNFAvltDbK5AzcOaR7yVzVGadr4YcCVxjKrEJOgi7WEOH8rUgCNB5cTD8N/Et GfZI+LGqSv0YtNa54T9D1AWJy08ZKkWvfGGIXN9UFAPMJ6OLLH/UUEgFa+7KlrEvMUupDFGnnR06 aDJAwtycb8yXtILj+TvfhLFhafxroXrflspavejQkEiHjNjtHnwbZ+o43g0/yxjwnarGI3kgcak7 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