linux-kernel - [PATCH] phy: Elimination the forced speed reduction algorithm.

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Date:	Wed, 27 Mar 2013 15:16:13 +0400
From:	Kirill Kapranov <kapranoff@...ox.ru>
To:	netdev@...r.kernel.org
Cc:	davem@...emloft.net, bhutchings@...arflare.com,
	peppe.cavallaro@...com, joe@...ches.com, bruce.w.allan@...el.com,
	linux-kernel@...r.kernel.org, Kirill Kapranov <kapranoff@...ox.ru>
Subject: [PATCH] phy: Elimination the forced speed reduction algorithm.

In case of fixed speed set up for a NIC (e.g. ethtool -s eth0 autoneg off speed
100 duplex full) with an ethernet cable plugged off, the mentioned algorithm
slows down a NIC speed, so further cable hook-up leads to nonoperable link state.

Signed-off-by: Kirill Kapranov <kapranoff@...ox.ru>
---
 drivers/net/phy/phy.c |   50 +------------------------------------------------
 1 files changed, 1 insertions(+), 49 deletions(-)

diff --git a/drivers/net/phy/phy.c b/drivers/net/phy/phy.c
index ef9ea92..828d4e6 100644
--- a/drivers/net/phy/phy.c
+++ b/drivers/net/phy/phy.c
@@ -463,33 +463,6 @@ void phy_stop_machine(struct phy_device *phydev)
 }
 
 /**
- * phy_force_reduction - reduce PHY speed/duplex settings by one step
- * @phydev: target phy_device struct
- *
- * Description: Reduces the speed/duplex settings by one notch,
- *   in this order--
- *   1000/FULL, 1000/HALF, 100/FULL, 100/HALF, 10/FULL, 10/HALF.
- *   The function bottoms out at 10/HALF.
- */
-static void phy_force_reduction(struct phy_device *phydev)
-{
-	int idx;
-
-	idx = phy_find_setting(phydev->speed, phydev->duplex);
-	
-	idx++;
-
-	idx = phy_find_valid(idx, phydev->supported);
-
-	phydev->speed = settings[idx].speed;
-	phydev->duplex = settings[idx].duplex;
-
-	pr_info("Trying %d/%s\n",
-		phydev->speed, DUPLEX_FULL == phydev->duplex ? "FULL" : "HALF");
-}
-
-
-/**
  * phy_error - enter HALTED state for this PHY device
  * @phydev: target phy_device struct
  *
@@ -818,30 +791,11 @@ void phy_state_machine(struct work_struct *work)
 				phydev->adjust_link(phydev->attached_dev);
 
 			} else if (0 == phydev->link_timeout--) {
-				int idx;
-
 				needs_aneg = 1;
 				/* If we have the magic_aneg bit,
 				 * we try again */
 				if (phydev->drv->flags & PHY_HAS_MAGICANEG)
 					break;
-
-				/* The timer expired, and we still
-				 * don't have a setting, so we try
-				 * forcing it until we find one that
-				 * works, starting from the fastest speed,
-				 * and working our way down */
-				idx = phy_find_valid(0, phydev->supported);
-
-				phydev->speed = settings[idx].speed;
-				phydev->duplex = settings[idx].duplex;
-
-				phydev->autoneg = AUTONEG_DISABLE;
-
-				pr_info("Trying %d/%s\n",
-					phydev->speed,
-					DUPLEX_FULL == phydev->duplex ?
-					"FULL" : "HALF");
 			}
 			break;
 		case PHY_NOLINK:
@@ -866,10 +820,8 @@ void phy_state_machine(struct work_struct *work)
 				phydev->state = PHY_RUNNING;
 				netif_carrier_on(phydev->attached_dev);
 			} else {
-				if (0 == phydev->link_timeout--) {
-					phy_force_reduction(phydev);
+				if (0 == phydev->link_timeout--)
 					needs_aneg = 1;
-				}
 			}
 
 			phydev->adjust_link(phydev->attached_dev);
-- 
1.7.2.5

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