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




On Wed 19 Apr 2017 at 20:39:35 +0200, Pascal Hambourg wrote:

> Le 19/04/2017 à 00:27, Brian a écrit :
> >On Wed 19 Apr 2017 at 00:12:15 +0200, Pascal Hambourg wrote:
> >
> >>Le 18/04/2017 à 21:14, Brian a écrit :
> >>>
> >>>However, my main point was that the kernel
> >>>identifying a card as a /dev/sdX disk does not imply it will necessarily
> >>>be visible to GRUB and bootable by it.
> >>
> >>If the card reader is idendified as /dev/sdX, then it probably behaves as a
> >>generic USB mass storage device and most BIOS can see it.
> >
> >A card in one of the slots of my card reader is identified as /dev/sdc1.
> >The reader itself is seen by lsusb. The BIOS doesn't see it and does not
> >have an option to boot from it. So I suppose my reader is not "most
> >BIOS". What is it behaving as?
> 
> How does lsusb identify the card reader ? What driver/module does it use ?
> "lsusb -t" will tell both.

root@test:~# lsusb
Bus 006 Device 002: ID 0644:0200 TEAC Corp. All-In-One Multi-Card Reader CA200/B/S

root@test:~# lsusb -t
/:  Bus 07.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
/:  Bus 06.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/6p, 480M
    |__ Port 2: Dev 2, If 0, Class=Mass Storage, Driver=usb-storage, 480M
/:  Bus 05.Port 1: Dev 1, Class=root_hub, Driver=ehci-pci/4p, 480M
/:  Bus 04.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
/:  Bus 03.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
/:  Bus 02.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
/:  Bus 01.Port 1: Dev 1, Class=root_hub, Driver=uhci_hcd/2p, 12M
    |__ Port 1: Dev 2, If 0, Class=Hub, Driver=hub/3p, 12M
        |__ Port 1: Dev 4, If 0, Class=Human Interface Device, Driver=usbhid, 12M
        |__ Port 1: Dev 4, If 1, Class=Human Interface Device, Driver=usbhid, 12M
    |__ Port 2: Dev 3, If 0, Class=Human Interface Device, Driver=usbhid, 1.5M

All external USB devices were disconnected, apart from the keyboard.

> If it uses usb-storage and the BIOS can boot from a USB device, then it
> surprises me that the BIOS cannot see and boot it when it contains a card
> with proper contents.

GRUB's 'ls' command shows

(hd0) (hd0,msdos5) (hd0,msdos1) (fd0)

when a CF card with Stretch on it is inserted before booting. (hd0) is a
SATA disk.

As I have detailed elsewhere,

https://lists.debian.org/debian-user/2017/04/msg00578.html

the card becomes visible to GRUB with its nativedisk command. The OP has
a reader which does not show an SD disk in GRUB and does not boot from
it. Perhaps he could take some time to see whether this command does
anything for him. His feedback (and that of others) would be
appreciated, The opinion about the inability to boot from an internal
card reader appears in need of revision.

(As an aside; I *can* boot the CF card from the reader in my printer!). 

-- 
Brian.