Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935727AbaBDWwM (ORCPT ); Tue, 4 Feb 2014 17:52:12 -0500 Received: from mail-pa0-f48.google.com ([209.85.220.48]:57166 "EHLO mail-pa0-f48.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932671AbaBDWwI (ORCPT ); Tue, 4 Feb 2014 17:52:08 -0500 MIME-Version: 1.0 In-Reply-To: <52F141AE.8010402@gmail.com> References: <1386513631-11284-1-git-send-email-sebastian.hesselbarth@gmail.com> <1386926429-28818-1-git-send-email-sebastian.hesselbarth@gmail.com> <20131217.144313.1563516273987934449.davem@davemloft.net> <52F141AE.8010402@gmail.com> From: Florian Fainelli Date: Tue, 4 Feb 2014 14:51:27 -0800 Message-ID: Subject: Re: [PATCH v2 0/5] net: phy: Ethernet PHY powerdown optimization To: Sebastian Hesselbarth Cc: David Miller , mugunthanvnm , netdev , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , Andrew Lunn Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Sebastian, 2014-02-04 Sebastian Hesselbarth : > On 12/17/2013 08:43 PM, David Miller wrote: >> >> From: Sebastian Hesselbarth >> Date: Fri, 13 Dec 2013 10:20:24 +0100 >> >>> This is v2 of the ethernet PHY power optimization patches to reduce >>> power consumption of network PHYs with link that are either unused or >>> the corresponding netdev is down. >>> >>> Compared to the last version, this patch set drops a patch to disable >>> unused PHYs after late initcall, as it is not compatible with a modular >>> mdio bus [1]. I'll investigate different ways to have a modular mdio bus >>> driver get notified when driver loading is done. >>> >>> Again, a branch with v2 applied to v3.13-rc2 can also be found at >>> https://github.com/shesselba/linux-dove.git topic/ethphy-power-v2 >>> >>> [1] http://www.spinics.net/lists/arm-kernel/msg293028.html >> >> >> Series applied, thanks. >> > > David, Mungunthan, Florian, > > as expected the above patches create a Linux to bootloader dependency > that surfaces dumb bootloaders not initializing PHYs correctly. > > Andrew has a Kirkwood based board that does not power-up and restart > auto-negotiation on the powered down PHY after a warm restart. While > this specific bootloader allows a soft-workaround by issuing the > required PHY writes before accessing the interface, others may not. > > I think we should allow the user to soft-disable the automatic > power-down of PHYs, i.e. by exploiting a kernel parameter. > > Do you have any preference for naming it? My call would be something > like libphy.suspend_halted = [0,1] with 1 being the default. The name looks good to me, and it would avoid having to clear the BMCR_PWRDOWN bit during the MDIO bus remove callback to workaround such bootloaders. BTW, it looks like we are omitting a 0.5 seconds delay after clearing the BMCR_PWRDOWN bit: " 22.2.4.1.5 Power Down ... A PHY is not required to meet the RX_CLK and TX_CLK signal functional requirements when either bit 0.11 or bit 0.10 is set to a logic one. A PHY shall meet the RX_CLK and TX_CLK signal functional require- ments defined in 22.2.2 within 0.5 s after both bit 0.11 and 0.10 are cleared to zero." -- Florian -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/