From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH net-next 0/3] net: phy: broken turn-around support Date: Tue, 12 May 2015 13:56:24 -0700 Message-ID: <555268F8.4030109@gmail.com> References: <1431442563-10218-1-git-send-email-bert@biot.com> <1431452006-3219-1-git-send-email-f.fainelli@gmail.com> <555265EE.9000009@biot.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, jogo@openwrt.org To: Bert Vermeulen , netdev@vger.kernel.org Return-path: Received: from mail-pd0-f170.google.com ([209.85.192.170]:36134 "EHLO mail-pd0-f170.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753691AbbELU4p (ORCPT ); Tue, 12 May 2015 16:56:45 -0400 Received: by pdea3 with SMTP id a3so26640605pde.3 for ; Tue, 12 May 2015 13:56:45 -0700 (PDT) In-Reply-To: <555265EE.9000009@biot.com> Sender: netdev-owner@vger.kernel.org List-ID: On 12/05/15 13:43, Bert Vermeulen wrote: > On 05/12/2015 07:33 PM, Florian Fainelli wrote: >> Hi all, >> >> This is an attempt at solving the broken turn-around problem in a way that >> is not specific to the mdio-gpio driver, since it affects different kinds of >> platforms. >> >> We cannot make that localized to PHY device drivers because probing the PHY >> device which has a broken turn-around can fail as early as in get_phy_id(), >> therefore we need a bit of help from Device Tree/platform_data. > > That is indeed a better place to put that ignore-ta flag, and the device > tree support is of course a big improvement over the previous patch as well. > > But it's still too big a hammer to hit the AR8316 problem with, I think. > Just like the previous patch, this disables checking TA on _all_ reads, but > I really only need it disabled on the first read. > > Are you saying you've seen other systems with this TA problem? Did those > have problems after more than just the first read? Yes, I have a bunch of boards here that use a Broadcom BCM53125 switch which is known not to release the line during turn-around time, and that is for all reads. A workaround is to discard the read failure indication from the MDIO controller, but to selectively do that, I would be keen on using the patches I just posted. -- Florian