Difference between revisions of "Talk:POWER9 Hardware Compatibility List/PCIe Devices"

From RCS Wiki
Jump to navigation Jump to search
 
(Fixed 40 bits are 1 TB (not 128 GB))
 
Line 7: Line 7:
 
> rendering them incapable of addressing host memory which lies above address 240. (Firmware patches to work around this are pending.)
 
> rendering them incapable of addressing host memory which lies above address 240. (Firmware patches to work around this are pending.)
  
2^40 means 128 GB of RAM. Does this mean I can still use this these PCIe devices without any unwanted side-effects if I do not have more than 128 GB RAM?
+
2^40 means 1 TB of RAM. Does this mean I can still use this these PCIe devices without any unwanted side-effects if I do not have more than 128 GB RAM?

Latest revision as of 10:21, 2 February 2020

What is the impact of incomplete PCIe address space (eg. 40 instead of 64 bits)?

This page says:

> Incomplete memory addressing support. The PCIe architecture specifies a 64-bit address space. > Some I/O devices try to economize on this by only implementing e.g. 40 bits for their addressing, > rendering them incapable of addressing host memory which lies above address 240. (Firmware patches to work around this are pending.)

2^40 means 1 TB of RAM. Does this mean I can still use this these PCIe devices without any unwanted side-effects if I do not have more than 128 GB RAM?