| 1 Jun 2025 |
 K900 | The fun part happens when you start adding dynamic configuration | 12:58:42 |
| K900 | Because that it's not prepared for | 12:58:46 |
| K900 | And that's why you have things doing SGMII layer autoneg | 12:59:00 |
| K900 | Because the EEPROM then just says "yeah I speak USXGMII" | 12:59:09 |
 emily | can it say it speaks both USXGMII and 2500BASE-X? | 12:59:22 |
| K900 | Technically yes | 12:59:27 |
| emily | I don't like that "technically" :P | 12:59:35 |
| emily | all of these things are going to want to do 10G after all | 12:59:43 |
| emily | since it's a 10G chip | 12:59:45 |
| K900 | I'm not sure things do generally | 12:59:46 |
| K900 | But you can and the kernel will basically pick the fastest least insane mode it can find | 13:00:09 |
| emily | right. which I could override if i specifically want 2500BASE-X | 13:00:38 |
| emily | (I assume) | 13:00:42 |
| K900 | Yes | 13:01:15 |
| K900 | Redacted or Malformed Event | 13:01:16 |
| emily | I'm a little worried that what I want may be unobtainium but I guess I'll have to try and find out. | 13:01:18 |
| K900 | Ugh | 13:01:19 |
| K900 | static const phy_interface_t phylink_sfp_interface_preference[] = {
PHY_INTERFACE_MODE_25GBASER,
PHY_INTERFACE_MODE_USXGMII,
PHY_INTERFACE_MODE_10GBASER,
PHY_INTERFACE_MODE_5GBASER,
PHY_INTERFACE_MODE_2500BASEX,
PHY_INTERFACE_MODE_SGMII,
PHY_INTERFACE_MODE_1000BASEX,
PHY_INTERFACE_MODE_100BASEX,
};
| 13:01:25 |
| K900 | This is the list the kernel uses | 13:01:30 |
| emily | when you ethtool -s sfp-wan advertise 0x20, what part of this whole system are you adjusting? | 13:02:37 |
| K900 | Technically it's both | 13:02:55 |
| K900 | (yay) | 13:02:57 |
| emily | ah, autonegotiation it looks like | 13:03:00 |
| emily | oh good it's both. | 13:03:10 |
| K900 | It is supposed to be for autonegotiation | 13:03:13 |
| K900 | But phylink does look at it in some places to also determine the SFP link properties sometimes | 13:03:31 |
| emily | I think that all of this sucks. | 13:03:42 |
| K900 | It definitely does yes | 13:03:49 |
| emily | how much would it cost to convince some SFP+ manufacturer on AliExpress to make me a custom module configured exactly how I want. | 13:03:58 |
| emily | all they have to do is flip a few bits. | 13:04:08 |
