From mboxrd@z Thu Jan 1 00:00:00 1970 From: Giuseppe CAVALLARO Subject: Re: [RFC] net: stmmac: keep RXC running in LPI mode to avoid system overload Date: Wed, 9 Oct 2013 17:28:06 +0200 Message-ID: <52557606.8030201@st.com> References: <1381244795-3922-1-git-send-email-romainba@abilis.com> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Cc: "David S. Miller" , , , Romain Baeriswyl To: Romain Baeriswyl Return-path: In-Reply-To: <1381244795-3922-1-git-send-email-romainba@abilis.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org Hello Romain On 10/8/2013 5:06 PM, Romain Baeriswyl wrote: > In order to avoid system overload, the clock RXC from the Phy should not be > stopped when in LPI mode. > > With the RTL8211E PHY which support EEE mode and with Apple Airport Extreme that > supports it also, the kernel get frozen as soon as some Ethernet transfers are hmm, I have a board with this transceiver so I could do some tests this could take a while, unfortunately. > on-going. System seems to be overloaded with too many interrupts. The 'top' > command reports often around ~80% irq. do you mean lpi mac interrupts? > > By letting the RXC clock running even in LPI mode as proposed below, the issue > seems solved. Is it the right way to proceed? For EEE capability, RX_CLK may be halted for this reason i used it as default in the stmmac and never seen your issue. > > What is the power impact to not stop RXC in LPI mode? I can point you to "22.2.2.8a Receive direction LPI transition" in IEEE802-3az... where is it reported that the PHY halt the RX_CLK in LPI mode. May I suspect some issues on your HW? or disable it with ethtool peppe > > --- > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 6 ++++-- > 1 files changed, 4 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > index e9eab29..d40d26b 100644 > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > @@ -314,7 +314,8 @@ bool stmmac_eee_init(struct stmmac_priv *priv) > /* MAC core supports the EEE feature. */ > if (priv->dma_cap.eee) { > /* Check if the PHY supports EEE */ > - if (phy_init_eee(priv->phydev, 1)) > + /* Keeps RXC running in LPI mode to avoid stability issue */ > + if (phy_init_eee(priv->phydev, 0)) > goto out; > > if (!priv->eee_active) { > @@ -770,7 +771,8 @@ static void stmmac_adjust_link(struct net_device *dev) > /* At this stage, it could be needed to setup the EEE or adjust some > * MAC related HW registers. > */ > - priv->eee_enabled = stmmac_eee_init(priv); > + if (new_state) > + priv->eee_enabled = stmmac_eee_init(priv); this seems out of context and not necessary > > spin_unlock_irqrestore(&priv->lock, flags); > } >