* Problem with MDI/MDI-X auto-switching in E100 driver
@ 2009-10-22 15:38 Eugene T. Bordenkircher
0 siblings, 0 replies; only message in thread
From: Eugene T. Bordenkircher @ 2009-10-22 15:38 UTC (permalink / raw)
To: netdev, linux-kernel; +Cc: linux.nics
Around line 1466 of e100.c (git master) is the following code to turn on
MDI/MDI-X auto-switching if it is not already.
} else 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 is broken in the case where an 8255x is used without magnetics. Per
Intel Application note 435, without the magnetics, auto switching is not
possible. The only way to turn this off without driver modifications is to set
the force_media flag via ethtool, which has the side effect of turning off all
auto-negotiation. This happens to be the case on a product I am currently
working on.
It seems a better solution to this is to trust the eeprom's configuration
rather than override it. Am I missing something or does this sound reasonable?
Eugene T. Bordenkircher
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2009-10-22 15:38 Problem with MDI/MDI-X auto-switching in E100 driver Eugene T. Bordenkircher
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