Raspberry Pi 4 SD-interface maximum clock frequency?

[lingon]

According to this block diagram of the BCM2711 (in german) the SD-interface on the Raspberry Pi 4 is designated as DDR50. Is the Arasan SDIO capable of running at higher frequencies like 100 MHz or 208 MHz or is it limited to 50 MHz maximum?

Is the block diagram an accurate representation of the BCM2711 or are there some errors in the diagram?

[Ernst]

Please rephrase your question after reading (and understanding) all the posts in this thread:viewtopic.php?f=29&t=256931

[lingon]

Thanks for pointing out the thread from last November. I had not read it previously. I'm curious to know if the SD-interface on the Raspberry Pi 4 can run at 104 MHz or not. If not then I'm curious to know where the hardware limitation is that restricts the clock frequency to 50 MHz.

[Ernst]

Thanks for pointing out the thread from last November. I had not read it previously. I'm curious to know if the SD-interface on the Raspberry Pi 4 can run at 104 MHz or not. If not then I'm curious to know where the hardware limitation is that restricts the clock frequency to 50 MHz.

Why ? viewtopic.php?t=244416#p1510284

[twrpi]

I have increased the frequency on the bus of my SD card to 208 MHz through system adjustments.
Unfortunately, the system is unstable in such a situation. It will lead to a system crash (required to reboot) or fail to write after hours.

[jdb]

I have increased the frequency on the bus of my SD card to 208 MHz through system adjustments.

How?