From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Cochran Subject: Re: [PATCH net-next] vlan: Pass ethtool get_ts_info queries to real device. Date: Sun, 23 Nov 2014 17:05:35 +0100 Message-ID: <20141123160533.GA4562@netboy> References: <1416575780-19132-1-git-send-email-richardcochran@gmail.com> <1416712512.7215.34.camel@decadent.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: netdev@vger.kernel.org, David Miller , Stefan =?iso-8859-1?Q?S=F8rensen?= To: Ben Hutchings Return-path: Received: from mail-wg0-f42.google.com ([74.125.82.42]:55895 "EHLO mail-wg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751273AbaKWQFl (ORCPT ); Sun, 23 Nov 2014 11:05:41 -0500 Received: by mail-wg0-f42.google.com with SMTP id z12so10316566wgg.1 for ; Sun, 23 Nov 2014 08:05:40 -0800 (PST) Content-Disposition: inline In-Reply-To: <1416712512.7215.34.camel@decadent.org.uk> Sender: netdev-owner@vger.kernel.org List-ID: On Sun, Nov 23, 2014 at 03:15:12AM +0000, Ben Hutchings wrote: > This assumes that the same PTP capabilities apply to VLAN-tagged frames. > I don't think it's at all safe to assume that RX filter modes other than > HWTSTAMP_FILTER_ALL will include VLAN-tagged frames. I think it is > necessary to define additional modes that explicitly include VLAN-tagged > frames. Unsafe? How? Do you mean that some HW cannot identify and time stamp PTP frames when VLAN tagged? That is surely disappointing for people who shell out money for such cards, but it is hardly unsafe. > I also disagree in general that reconfiguring a VLAN device should make > changes to the underlying device that affect more than just that VLAN, > i.e. SIOCSHWTSTAMP should not be passed through. SIOCGHWTSTAMP could be > passed through, but rx_filter would need adjustment (VLAN-tagged modes > on the underlying devices become untagged modes on the VLAN device). The whole filter list with every last combination (at least, the ones at the time) came directly from a early, limited HW design. Sane, modern PTP hardware provides time stamps regardless of whether a frame is VLAN tagged or not. I don't see any reason not to make our stack even more ugly just to cater to broken hardware. I have nothing against adding VLAN to the SIOCGHWTSTAMP list, because the hardware people *really* use all have: HWTSTAMP_TX_ON, and HWTSTAMP_FILTER_ALL, or HWTSTAMP_FILTER_PTP_V2_EVENT, So adding more won't hurt. (But it won't help either. If your HW cannot time stamp Layer2 and you transmit Layer2, you simply never get a time stamp.) But please don't hold up progress just for this sort of thing. Thanks, Richard