Commit 655c9141 authored May 23, 2019 by Mauro S. M. Rodrigues Committed by Jeff Kirsher Jun 26, 2019

ixgbe: Check DDM existence in transceiver before access



Some transceivers may comply with SFF-8472 but not implement the Digital
Diagnostic Monitoring (DDM) interface described in it. The existence of
such area is specified by bit 6 of byte 92, set to 1 if implemented.

Currently, due to not checking this bit ixgbe fails trying to read SFP
module's eeprom with the follow message:

ethtool -m enP51p1s0f0
Cannot get Module EEPROM data: Input/output error

Because it fails to read the additional 256 bytes in which it was assumed
to exist the DDM data.

This issue was noticed using a Mellanox Passive DAC PN 01FT738. The eeprom
data was confirmed by Mellanox as correct and present in other Passive
DACs in from other manufacturers.

Signed-off-by: "Mauro S. M. Rodrigues" <maurosr@linux.vnet.ibm.com>
Reviewed-by: Jesse Brandeburg <jesse.brandeburg@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>

parent 3b525691

drivers/net/ethernet/intel/ixgbe/ixgbe_ethtool.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -3226,7 +3226,8 @@ static int ixgbe_get_module_info(struct net_device *dev,
		page_swap = true;
		}

		if (sff8472_rev == IXGBE_SFF_SFF_8472_UNSUP \|\| page_swap) {
		if (sff8472_rev == IXGBE_SFF_SFF_8472_UNSUP \|\| page_swap \|\|
		!(addr_mode & IXGBE_SFF_DDM_IMPLEMENTED)) {
		/* We have a SFP, but it does not support SFF-8472 */
		modinfo->type = ETH_MODULE_SFF_8079;
		modinfo->eeprom_len = ETH_MODULE_SFF_8079_LEN;

drivers/net/ethernet/intel/ixgbe/ixgbe_phy.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@
		#define IXGBE_SFF_SOFT_RS_SELECT_10G 0x8
		#define IXGBE_SFF_SOFT_RS_SELECT_1G 0x0
		#define IXGBE_SFF_ADDRESSING_MODE 0x4
		#define IXGBE_SFF_DDM_IMPLEMENTED 0x40
		#define IXGBE_SFF_QSFP_DA_ACTIVE_CABLE 0x1
		#define IXGBE_SFF_QSFP_DA_PASSIVE_CABLE 0x8
		#define IXGBE_SFF_QSFP_CONNECTOR_NOT_SEPARABLE 0x23

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