e100 MDI/MDIX bug(?)
Subsystems (2)
PATCH 1/1 e100 MDI/MDIX bug(?)
e100_phy_init() contains the following code to conditionally enable MDI/MDI-X Autodetection on newer e100 chips:
if((nic->mac >= mac_82550_D102) || ((nic->flags & ich) &&
(mdio_read(netdev, nic->mii.phy_id, MII_TPISTATUS) &
0x8000) &&
(nic->eeprom[eeprom_cnfg_mdix] & eeprom_mdix_enabled)))
/* enable/disable MDI/MDI-X auto-switching */
mdio_write(netdev, nic->mii.phy_id, MII_NCONFIG,
nic->mii.force_media ? 0 : NCONFIG_AUTO_SWITCH);This code seems to include 4 problems:
1. e100_eeprom_load was called after e100_phy_init...
2. If the chip revision is >= mac_82550_D102 it enables the feature unconditionally, disregarding the eeprom.
3. According to Intel's errata, MDI/MDI-X Autodetection should never be enabled on 82551ER or 82551QM chips (see
http://developer.intel.com/design/network/specupdt/82551ER_si.pdf).
4. If the eeprom disables the feature, it should be actively disabled, and not left as default.
suggested patch against 2.6.10 attached. An alternative would be to forcibly disable the feature for all chips with (nic->mac >= mac_82550_D102), as I'm not sure if there are chips for which it IS supported.
Signature · 3 lines
Eran Mann MRV International www.mrv.com
drivers/net/e100.c +15 -7
@@ -1074,11 +1074,19 @@ }if ((nic->mac >= mac_82550_D102) || ((nic->flags & ich) && - (mdio_read (netdev, nic->mii.phy_id,MII_TPISTATUS ) &0x8000 ) && - (nic->eeprom[eeprom_cnfg_mdix] & eeprom_mdix_enabled))) -/* enable/disable MDI/MDI-X auto-switching */ -mdio_write (netdev, nic->mii.phy_id,MII_NCONFIG , - nic->mii.force_media ?0 :NCONFIG_AUTO_SWITCH ); + (mdio_read (netdev, nic->mii.phy_id,MII_TPISTATUS ) + &0x8000 ))) { +/* enable/disable MDI/MDI-X auto-switching. +According to errata MDI/MDI-X auto-switching should +be disabled for 82551ER/QM chips */ +if ((nic->mac == mac_82551_E) || (nic->mac == mac_82551_F) || + (nic->mac == mac_82551_10) || (nic->mii.force_media) || + !(nic->eeprom[eeprom_cnfg_mdix] & eeprom_mdix_enabled)) +mdio_write (netdev, nic->mii.phy_id,MII_NCONFIG ,0 ); +else +mdio_write (netdev, nic->mii.phy_id,MII_NCONFIG , +NCONFIG_AUTO_SWITCH ); + }return 0 ; }
@@ -2248,11 +2256,11 @@ goto err_out_iounmap; } -e100_phy_init (nic); -if ((err =e100_eeprom_load (nic))) goto err_out_free; +e100_phy_init (nic); +memcpy (netdev->dev_addr, nic->eeprom,ETH_ALEN );if (!is_valid_ether_addr (netdev->dev_addr)) { DPRINTK(PROBE, ERR, "Invalid MAC address from "