Debian-Pi-Aarch64/docs/notes/pi4_cpu_stepping.md

36 lines
786 B
Markdown

# BCM2711 SoC Version about stepping
## 2711ZPKFSB06B0T & 2711ZPKFSB06C0T
The stepping "**C0T**" is newer than "**B0T**".
Run the command to check:
```
od -An -tx1 /proc/device-tree/emmc2bus/dma-ranges
```
It will show different output depending on the stepping:
#### B0
````
pi@raspberrypi:~$ od -An -tx1 /proc/device-tree/emmc2bus/dma-ranges
00 00 00 00 c0 00 00 00 00 00 00 00 00 00 00 00
40 00 00 00
````
#### C0
```
pi@raspberrypi:~$ od -An -tx1 /proc/device-tree/emmc2bus/dma-ranges
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
fc 00 00 00
```
In the case of the BCM2711, it looks like the two main fixes are related to RAM addressing:
- 1.The EMMC2 bus can only directly address the first 1GB.
- 2.The PCIe interface can only directly address the first 3GB.