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Vadim Pasternak authored
[ Upstream commit f1436c80 ] Prevent reading unsupported slave address from SFP EEPROM by testing Diagnostic Monitoring Type byte in EEPROM. Read only page zero of EEPROM, in case this byte is zero. If some SFP transceiver does not support Digital Optical Monitoring (DOM), reading SFP EEPROM slave address 0x51 could return an error. Availability of DOM support is verified by reading from zero page Diagnostic Monitoring Type byte describing how diagnostic monitoring is implemented by transceiver. If bit 6 of this byte is set, it indicates that digital diagnostic monitoring has been implemented. Otherwise it is not and transceiver could fail to reply to transaction for slave address 0x51 [1010001X (A2h)], which is used to access measurements page. Such issue has been observed when reading cable MCP2M00-xxxx, MCP7F00-xxxx, and few others. Fixes: 2ea10903 ("mlxsw: spectrum: Add support for access cable info via ethtool") Fixes: 4400081b ("mlxsw: spectrum: Fix EEPROM access in case of SFP/SFP+") Signed-off-by:
Vadim Pasternak <vadimp@mellanox.com> Acked-by:
Jiri Pirko <jiri@mellanox.com> Signed-off-by:
Ido Schimmel <idosch@mellanox.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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