micro SD cards not recognized

[Şerban S.]

[member=25275]Şerban S.[/member]
[...] Lenovo ideapad 100S-14IBR [...] Intel Celeron N3050 [...]

Hi!
Thanks for taking the time to provide the info.
Now... given the data, it looks like we have a machine very much like my ASUS X200MA.
My main problem with this machine was/is the amount of USB ports (slots). Only 3 and I use a mouse and an external keyboard. While I never noticed trouble using MicroSDs, from time to time, I still need to use a card reader, since sometimes I need to access data from more than 1 card...
HOW DID OVERCOME THE LACK OF USBs:
Given the configuration, I assume you have at least an USB 3.0 port (I have one).
This allows you to use an USB 3.0 Hub that will expand the ports from 3 to 6.
You can use this way any external USB device you might need at some point.
From my experience, using this kind of hub, allows you to perform low level backups (CloneZilla) without causing issues related to the USB storage devices, even if you use a keybord and a mouse. I tested that many times and so far, it worked OK.
However...
Before having the USB 3.0 hub, I encountered trouble when using a USB 2.0 hub for the mouse and keyboard. After starting CloneZilla, the reading devices routine had trouble identifying the external HDD so I had to switch devices and ports, until the problem got solved which, I must admit, was awfully annoying...
Further more, sometimes I had trouble booting CloneZilla, because the ASUS netbook has an UEFI firmware exactly like the Ideapad we're analysing here.
My best guess is that the real problem is the way the IRQs are managed. And this looks to be someting done on purpose by the manufacturers.
Although there are many IRQs available, there are only 3 or 4 of them in use and at least one, is SHARED, which leads to countless impredictible trouble, related to the devices that are attached to the computer through various ports.
One of those kind of troubles, is the way the CARD READER works (or... fails to do so...).
Usually, the TouchPad and the card reader, share the SAME IRQ with one USB port, even with two, which leads to hardware conflicts more often than expected, due to drivers resources overlap.
The USB 3.0 hub I'm refering to, is about 12 euros (meaning some $13 or $14 at most) so this might solve many other problems, beside the SD cards reading one.
With those said. I hope this info will help you reconsider your strategiy regarding the use of an external card reader.
As Jerry pointed before, the kernel problem looks difficult to solve. As I mentioned, my best guess is that the real problem is the IRQ assignment, which is also a trouble extremely difficult to solve if it is by design (hardware limitation), which I suspect is on purpose, namely, to force us to buy something more expensive.
My best regards!