From mboxrd@z Thu Jan 1 00:00:00 1970 From: Florian Fainelli Subject: Re: [PATCH v3 1/2] net: phy: Fix PHY AN done state machine for interrupt driven PHYs Date: Wed, 19 Apr 2017 09:28:00 -0700 Message-ID: <42a72e93-8c10-a4b3-8c0f-d3350fc5e2c1@gmail.com> References: <1490180524-28675-1-git-send-email-rogerq@ti.com> <1490180524-28675-2-git-send-email-rogerq@ti.com> <078917ad-77a1-a722-1688-6203ae183a46@ti.com> <203afff4-7dd7-e185-000a-1689a97dfb67@ti.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Cc: davem@davemloft.net, kyle.roeschley@ni.com, nsekhar@ti.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, "stable # v4 . 9+" , Sergei Shtylyov , "Andrew F. Davis" , Alexander Kochetkov To: Roger Quadros , andrew@lunn.ch Return-path: In-Reply-To: <203afff4-7dd7-e185-000a-1689a97dfb67@ti.com> Sender: stable-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On 04/11/2017 04:17 AM, Roger Quadros wrote: > Hi, > > On 28/03/17 13:05, Roger Quadros wrote: >> +Andrew Davis & Sekhar. >> >> Hi, >> >> Andrew Davis posted a few comments offline which I'm clarifying here. >> >> On 27/03/17 14:59, Roger Quadros wrote: >>> The Ethernet link on an interrupt driven PHY was not coming up if the >>> Ethernet cable was plugged before the Ethernet interface was brought up. >>> >>> The PHY state machine seems to be stuck from RUNNING to AN state >>> with no new interrupts from the PHY. So it doesn't know when the >>> PHY Auto-negotiation has been completed and doesn't transition to RUNNING >>> state with ANEG done thus netif_carrier_on() is never called. >>> >>> NOTE: genphy_config_aneg() will not restart PHY Auto-negotiation of >>> advertisement parameters didn't change. >> >> Is phy->config_aneg expected to *always* restart auto-negotiation even if >> advertisement parameters didn't change? >> If so then we'll need to fix genphy_config_aneg(). >> >>> >>> Fix this by scheduling the PHY state machine in phy_start_aneg(). >>> There is no way of knowing in phy.c whether auto-negotiation was >>> restarted or not by the PHY driver so we just wait for the next >>> poll/interrupt to update the PHY state machine. >>> >>> Fixes: 3c293f4e08b5 ("net: phy: Trigger state machine on state change and not polling.") >>> Cc: stable # v4.9+ >>> Signed-off-by: Roger Quadros >>> --- >>> v3: Fix typo in commit message >>> >>> drivers/net/phy/phy.c | 4 ++++ >>> 1 file changed, 4 insertions(+) >>> >>> diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c >>> index 1be69d8..49dedf8 100644 >>> --- a/drivers/net/phy/phy.c >>> +++ b/drivers/net/phy/phy.c >>> @@ -630,6 +630,10 @@ int phy_start_aneg(struct phy_device *phydev) >>> >>> out_unlock: >>> mutex_unlock(&phydev->lock); >>> + if (!err && phy_interrupt_is_valid(phydev)) >>> + queue_delayed_work(system_power_efficient_wq, >>> + &phydev->state_queue, HZ); >>> + >>> return err; >>> } >>> EXPORT_SYMBOL(phy_start_aneg); >>> >> >> There is still room for optimization for interrupt driven PHYs as I still >> see a delay of 1 second between "ifconfig ethx up" and link status coming up >> if cable was already plugged in. In fact if Auto-negotiation was already completed >> and not required to be restarted, the PHY state machine should have move from >> AN to RUNNING instantly without expecting a PHY interrupt. >> >> How can we get rid of the unnecessary delay in the case where auto-negotiation >> is not restarted? >> Should we check for phy_aneg_done() immediately after issuing a phy_start_aneg() >> in phy_state_machine() and switch from PHY_AN to PHY_RUNNING? That sounds like a good idea yes. It seems to me like Alexander's patch actually takes care of that: http://patchwork.ozlabs.org/patch/752288/ Let's try to merge threads/recipients so we can shoot for a fix to be included soon. Thanks! >> >> This should avoid the need to re-schedule the state machine in phy_start_angeg(). > > Any comments on my questions? > > cheers, > -roger > -- Florian