Hello,

I have following situation:
- one SD card (4 GB) gets recognized via built-in card reader (Thinkpad X61 and Dell D420), but does not via USB-connected card reader. The card reader itself is OK, I checked with another SD card.

Here are some data about card:
- when it is connected (built-in reader), it is shown as device "/dev/mmcblk0p1", file system shown as "W95 FAT32".
- another SD card is mounted as "/dev/sdb1", and filesystem is (according to GParted) FAT32.

I do not understand, why the bigger card is handled differently via USB card reader than via built in reader. I would appreciate any hint.

regards,
Andrey

Bigger card = older card. That's the biggest difference.

There are always plugging issues with those cards, or adapters. There are also usb adapters which try to cover camera sd cards as well and have very iffy pluggins systems.

My advice - Use it in the pcs card readers, and get suspicious of the usb reader, especially if it was cheap or was given away in a breakfast cereal packet.

/dev/mmcblk0p1 looks strange, /dev/sdb1 is common.

Possible issues:

• Build-in card reader handles 4+ GB cards differently as compared to to cards ≤ 2 GB.
• USB card reader cannot handle cards > 2 GB.
• Your 4 GB card is a non-standard "SD card". These non-standard cards exist. Standard "SD cards" are limited to 2 GB. According to standard, 4 GB cards are "SDHC cards".

Hello
I have to correct myself: when I connect bigger card via USB-reader, it is mounted under /dev/sdc and its size is shown as 2 TB.

The card was already formatted in my camera (Casio Exilim).

I suppose, this can be a reason - size larger than 2 GB.
Update: the card itself is not SDHC, but just SD. I also found out that card reader in X61t (laptop I used for tests) is capable of reading SD HC cards.
Regards,
A.

On the names: /dev/sdX goes to internal & external disks. Built in card readers get /dev/mmcblkXpN where
X=0,1,2… for 1st, second, third sd card.
N=1,2,3,… partition numbers on the sd card. As most can only read/write a single card, you rarely see anything other than mmcblk0p1

I have put the same micro sdcard into one adapter for my card reader, and it's mmcblk0p1 & mmcblk0p2. Then I have a usb adapter for micro sdcards, and in that it was sdc1 & sdc2 when it was plugged into usb.

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Because USB hardware and internal hardware is not the same thing. If you configure the Linux Kernel, you will see that there is a huge section just for USB and all kind of USB gadgets and stuff.

Some internal hardware (inside the laptop) actually uses the universal serial bus interface instead of more normal interfaces, this includes some webcams and some card readers too actually. I had this issue once with a realtek or a broadcom card reader, and I just couldn't figure out why it was not recognized although I had included ALL the realtek/broadcom card reader drivers (and all the memory cards etc). In the end I found out that the solution was to install the USB card reader driver, because it was on the universal serial bus inteface even though it was inside my laptop.

Hello,
I managed to find a couple of other cards (8 GB and 2 GB), and I could prove, that internal card reader of my X61 reads everything, and that USB card reader by "Vivanco" (chip Alcor Micro, USB ID 058f:6362) reads only cards up to 2 GB.

Further, I found a post on ArchLinux-forum asking exactly the same. The answer was, that the reader itself simply cannot read SDHC cards. I suppose, I have the same issue.

Lenovo made its SD-cardreader "SDHC-comaptible" just by installing certain updates. So, it is same hardware, but another way of using. Just wondering, if I can enforce proper reading of SD HC card in the "ordinary" SD-reader under Linux.

Regards,
Andrey

Hmm yeah, sorry, I could probably tell you more, but I never figured out all the "memory card" stuff in the Kernel, since I almost never used all the different cards or any cards in general. Just looking at it generally when I deal with the Kernel, the "card" stuff is confusing, and I don't mean the card reader, but the section for different memory cards and all that.

Perhaps it could have something to do with one of those settings, it is at least worth checking out. It's several sections and alot of different named and types of "cards". I guess you COULD try to just compile it all as modules, or perhaps there is a bug where something is a module, and the module doesn't load when you use the kind of related card (technicall it's hotplugging?). So perhaps build them all into the Kernel for testing, check if it works, if not then remove or make modules of the ones that are least likely related to your one.

One of my SD cards could not be read anywhere, 16G kingston.
What happened is that it corroded a bit, so I cleaned the copper with rubber eraser, all good now.
Possibly not related to OP problem, just saying.

sdcards have a very limited number of write cycles. So I buy around 32G and not 500G because I don't want to lose 500G of data!

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Hello,
no, I will not spend time on it. I have an external USB hard drive for larger files, and 1 USB stick of 4 GB. But I'm really surprised, that my 15 years old Thinkpad Z61t running 32 bit Linux Ubuntu can detect 16 GB SD-card, and younger card reader (but via USB) on more modern Linux cannot. Somehow not really "linux-alike" :-)

Regards,
Andrey

Why blame linux and not your usb sdcard reader?

1 members found this post helpful.