Right SFP EEPROM config for DFP-34X-2C2 to work automatically work at 2500base-X?

[Headcrabed]

Seems ODI has multiple wrong configuration on DFP-34X-2C2's eeprom. And this blocks linux to use 2500base-X by default.

First, they set BR, Nominal value to 1300MBd, while it should be 3125MBd(Since 3125 cannot be set, it should be round off to 3100MBd).

Second, 1000base-LX is enabled by default, so that linux would prefer that speed (https://github.com/torvalds/linux/blob/cf1182944c7cc9f1c21a8a44e0d29abe12527412/drivers/net/phy/sfp-bus.c#L327)

After disabling 1000base-LX and set BR, Nominal value to 3100MBd in EEPROM, my device (Banana pi BPI-R3 + Openwrt 23.05.2) would use 2500base-X by default now.

For example:

Set addr 0x06 to 0x00(Disable 1000base-LX), addr 0x0c to 0x1f(3100MBd), addr 0x3f to 0x80(Checksum)

[Anime4000]

to change this, do you use SFPTotal Whistle or Mini ?

[Headcrabed]

@Anime4000 Emmm.. What do you mean? If you mean linux support of 2500base-x on sfp module, seems it has been supported at least since 4.16-rc1: torvalds/linux@f10fcbc

[Anime4000]

I mean: Disable 1000base-LX + 0x1f (3100MBd), refering to git blame, the change was 6 month ago, I wonder this method support older Linux Kernel

[Headcrabed]

That's 6 years ago.. And I didn't find code for 3100MBd support on earlier versions of kernel.

[Anime4000]

based on this change:
torvalds/linux@466b97b
it committed on Nov 17, 2023

code change before if (bitmap_empty(modes, __ETHTOOL_LINK_MODE_MASK_NBITS) && br_nom) should give same results?

[Headcrabed]

I think it should behave the same before and after the commit you mentioned

[duskyzaoKING]

Can you share the .bin of the entire firwmare with this modification ? will use a programer to flash direct in SOP

[Headcrabed]

Ok, I will do it later. But I still prefer you to do the modification by yourself, or you will lose your date code and serial number.

[duskyzaoKING]

Didnt thinked about it. I think its best i do. thanks

[Headcrabed]

dump_eeprom.zip
This is the dump of addr 0x50 of my eeprom

[lehoangnb]

I found this command can change EEPROM value, but eeprom content does not same as I read from chip using programer, anyone can check it work or not?
diag i2c set port 1 dev 0x50 reg 0x06 data 0x0
(For checksum, use diag i2c get port 1 dev 0x50 reg ... to dump all eeprom content from 0x00 to 0x3E and use SFPTotal to calculate)

[Anime4000]

I tried this, diag i2c wont write to it, I wonder if there easy way to write internally

[lehoangnb]

Yes, I think its is dummy eeprom, the value remain after reboot but doesn't same as real eeeprom
I have dump all value from i2c diag

[Anime4000]

I tried

Addr	Value
0x06	0x00
0x0c	0x1F

Mikrotik detect as this instance

The way Mikrotik show supported are different, I wonder what value to make 2.5G baseX in supported list

[Headcrabed]

@Headcrabed here NIJK24000001.zip

@lehoangnb maybe buy 2.5G/1G RJ45 SFP and copy the EEPROM see what position is use

Seems everything is right. So that's Mikrotik's fault if you are sure yore device supports 2.5G mode.

[Anime4000]

if buy 2.5/1G RJ45 SFP and copy the EEPROM would work? but it become 2.5G baseT

@Headcrabed
2.5G just work by disable auto nego and set to 2.5G baseX, I tried 2.5G baseT also works. I just wondering if SFP Support list show 2.5G baseX and can use auto nego

[Headcrabed]

That's Mikrotik's fault to not supporting auto negotiation.

[Anime4000]

if I buy RJ45 2.5G/1G and copy it's EEPROM, will it work?

[Headcrabed]

Nope, it won't help.

[ifplusor]

I test this on Banana Pi BPI-R4, it's work.