04-23-2020, 05:54 AM
> rockpro64-nocapacitors2.jpg
I saw the jpg you posted, it's probably a board that's already fixed.
I think that the resistance "R89506 / R89507" was changed to 0Ω and the capacitor "C50007 / C50008" was left as it was.
This is exactly what I did.
The impedance of the PCIE transmission line is specified as 50Ω.
For this standard, the effect of the capacitor "C50007/C50008" is 1Ω or less, and even if there is, it has almost no effect.
On the other hand, the resistors has an error of +50Ω or more with respect to the standard value of 50Ω, which is an unacceptable error.
You can check whether it is working properly by the following method.
> I am getting only 560-580 MB/s in `hdparm --direct -t` test with a Samsung 970 Evo that...
Please refer to the post below.
The Performance varies depending on the kernel type and test method.
https://forum.pine64.org/showthread.php?...1#pid39681
I saw the jpg you posted, it's probably a board that's already fixed.
I think that the resistance "R89506 / R89507" was changed to 0Ω and the capacitor "C50007 / C50008" was left as it was.
This is exactly what I did.
The impedance of the PCIE transmission line is specified as 50Ω.
For this standard, the effect of the capacitor "C50007/C50008" is 1Ω or less, and even if there is, it has almost no effect.
On the other hand, the resistors has an error of +50Ω or more with respect to the standard value of 50Ω, which is an unacceptable error.
You can check whether it is working properly by the following method.
Code:
# lspci -vvv | grep Speed
LnkCap: Port #0, Speed 5GT/s, Width x4, ASPM L1, Exit Latency L0s <256ns, L1 <8us
=> LnkSta: Speed 5GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
LnkCtl2: Target Link Speed: 5GT/s, EnterCompliance- SpeedDis-
LnkCap: Port #0, Speed 8GT/s, Width x4, ASPM L1, Exit Latency L0s <1us, L1 <8us
=> LnkSta: Speed 5GT/s, Width x4, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-> I am getting only 560-580 MB/s in `hdparm --direct -t` test with a Samsung 970 Evo that...
Please refer to the post below.
The Performance varies depending on the kernel type and test method.
https://forum.pine64.org/showthread.php?...1#pid39681