If you hold Ctrl key while clicking on a already assigned (green) pin, CubeDE/MX shows you alternative pins (blue) where you can reassign the pin function by drag&drop. But, in your case, it worked for me without any reassignments, maybe I'm missing some constraints:
If you don't like clicking, there are tables in the data sheet where you can play an "8 queens" like pin assignment game.
Yes, I forgot to mention one more piece of data: I also have USB_OTG_FS selected as "Device_Only".
(I updated my initial post to include USB_OTG_FS.)
If I deselect it, then my SDIO is OK with no yellow icon beside it.
Is it truly due to pin assignments or something else?
I first thought that it was because of pin assignments.
However, when selecting only USB_OTG_FS as "Device_Only", and disabling SDIO, only PA11 and PA12 pins are set.
When selecting only SDIO as "SD 4 bits Wide bus", and disabling USB_OTG_FS, the pins that are set are:
PC8, PC9, PC10, PC11, PC12, and PD2.
Therefore, it doesn't look like there are pin conflicts?
If I have SDIO selected with CAN, I2C, and UART, but without USB_OTG_FS, everything is fine.
When I add USB_OTG_FS, then the warning icon comes beside SDIO.
When I move my mouse over the caution icon, the tool-tip message appears with text as follows:
Partly disabled conflict with:
CAN1: Master Mode
But again, CAN is using different pins--PB8 and PB9.
The following is my screen shot:
Please assist.
Warning is not problem only report that some function here SDIO is impossible,
for your config was in conflict MMC8bits mode SDIO
