The SD card on thinkpad P52 is connected to PCIe bus:
70:00.0 Unassigned class [ff00]: Realtek Semiconductor Co., Ltd. RTS525A PCI Express Card Reader (rev 01)
After a latest upgrade (I upgrade the system to nixos 19.09 recently), the reader will not notify and will not create corresponding node in /dev (i.e., /dev/mmcblk*) when I insert the card into the reader.
The notification from plasma5 and the creation of /dev/mmcblock* will only happen after I manually run the command
lspci as an ordinary user in the terminal.
It seems that the kernel only query the status of the sd card reader when the command
lspci is launched.
My system version is
the kernel version is
Linux localhost 4.19.71 #1-NixOS SMP Fri Sep 6 10:40:02 UTC 2019 x86_64 GNU/Linux
The sd card read just works fine under windows10. And if ac supplier is connected, it is also normal.
Does anyone else see the same problem?