PCIe显卡，16对 Receive 信号是闲置的吗？

Quantum_

1. x16 的显卡， 共有HSI(0)n/p ~ HSI(15)n/p 16对Receive信号（显卡到CPU）.
# j: r- u2 P; |5 `0 r2. 显卡只是一个输出设备，只接收CPU的输出， 并不需要与CPU高速交互。
7 @" Z+ q* w, Z& A) X8 l3. 那么， 第1点描述的16对线， 是否就一直是闲置的？ (这么浪费，有点不可思议！特发此问）
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**参考文书：
% S: u$ f" U- j' B5 chttps://en.wikipedia.org/wiki/PCI_Express

6 \7 h2 Z* k! b谢谢！

超級狗

PCI Express Basics and Background
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Quantum_

Dear Super
I still can't understand what happened to PCIe receiver signals to make them transmit signal from Device to Host, after reading your attachment carefully.
/ z! R1 t+ k) m. CDo you mean that the answer of my question is concluded in the chapter below?
"Credit-based flow control is point-to-point based, not end-to-end, "
or
2 _7 [/ n7 N* C# [; G5 p9 I) Z"Split Transactions"


Do you have any other stuff for a rookie EE to learn about the PCIe Dispaly Card.
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Thanks very much.

ykwym

PCIe的有些包发出来是需要接收端发信息回去，确保包是一定被收到的。so。。。