3 ms·

I came across this in a manual/datasheet: >16.Link Width Negotiation in the Presence of Bad Lanes >In an effort to maximize the link width when one or more la

I came across this in a manual/datasheet: >16.Link Width Negotiation in the Presence of Bad Lanes >In an effort to maximize the link width when one or more lanes of a multi-lane link are not functioning correctly (i.e., reliable communication of training sets across the lane is not possible), PES64H16G2 down-stream switch ports automatically attempt a lane reversed configuration when doing so has the potential to enhance the achievable link width.For example, if lane 1 of a x4 link is not operating correctly, the device's downstream switch port attached to the link attempts a lane reversed configuration to form a x2 link using lanes 2 and 3 (Figure 7.4(d)). If the link partner accepts the lane reversed configuration, the optimal x2 link will be formed using lanes2 and 3. If the link partner does not accept the lane reversed configuration, but instead requests a lane configuration supported by the PES64H16G2 (e.g., x1 link using lane 0), the device accepts the configuration and forms the reduced width link. Otherwise, if the lane numbering agreement fails, the device automatically re-trains the link from the Detect state. During this re-training, the PES64H16G2 port does not re-attempt a lane reversed configuration, but rather tries to form the link without reversing the lanes. As a result, a x1 link is formed using lane 0 (Figure 7.4 (e)). My guess is it's likely a bad BGA solder ball on Lane1, or possibly ESD damage if you took the SSD out and molested it or rubbed it on a cat right before it broke. Does it indicate it's using reversed lanes?

zamadatix 2y ago
Nice digging, that lines up perfectly with the observed behavior! I'll have to poke around and see if anything indicates that's the operational mode to be sure. The failure mode was that one day I just noticed it was copying sequential data from another drive slower than it normally did. Don't recall it ever having been touched after install (it is the heatsinkless variant of the T705 4TB mounted on the motherboard m.2 hearsink for that slot). Temps always reported quite reasonable, even when under stress bench load (which was rare, the drive was just a secondary drive for loading games). Since then it's been popped between about 10 boards in confusion though haha. No cat yet!

zamadatix 2y ago

Nice digging, that lines up perfectly with the observed behavior! I'll have to poke around and see if anything indicates that's the operational mode to be sure. The failure mode was that one day I just noticed it was copying sequential data from another drive slower than it normally did. Don't recall it ever having been touched after install (it is the heatsinkless variant of the T705 4TB mounted on the motherboard m.2 hearsink for that slot). Temps always reported quite reasonable, even when under stress bench load (which was rare, the drive was just a secondary drive for loading games). Since then it's been popped between about 10 boards in confusion though haha. No cat yet!