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Re: Possibly erroneous "device not present" message during boot

Le 17/04/2017 à 21:05, Brian a écrit :
On Mon 17 Apr 2017 at 08:48:50 +0000, Curt wrote:

On 2017-04-17, David Wright <deblis@xxxxxxxxxxxxxxxxx> wrote:

Oddly, this ancient laptop (Acer) has a slot that makes the SD card
look like a /dev/sdX disk, and the BIOS is happy to boot from it.

I have an Acer X1430 with an internal "Multi-in-1 Media Card Reader" for
which an SD card inserted into the reader is recognized by the kernel as
as a /dev/sdX disk.

You have to be careful here to distinguish between what the OS can
recognise and what GRUB can see. The kernel will be using the Multimedia
Card device drivers to detect the device

Not always. If the card reader identifies itself as a generic USB mass storage device, then the kernel will use the same drivers as for USB drives and assign the same kind of name /dev/sd*. It seems that in this case, most BIOS recognize it and can boot from it.

I guess that the kernel will use MMC device drivers only if the card reader identifies itself as a native SD/MMC card reader.