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I'm new to Raspberry Pi and I wanted to use an external hard drive as my primary storage.. so went and got a Seagate BUP Slim BK 1TB HDD. It is not externally powered. My Pi is set up with Raspbian, and is up to date.

When I turn on the device and run sudo fdisk -l I only see my SD card. So when I run dmesg to check the log messages, this is the relevant set of messages:

[    4.837878] usb 1-1.4: new high-speed USB device number 5 using dwc_otg
[    5.200091] usb 1-1.4: New USB device found, idVendor=0bc2, idProduct=ab24
[    5.227777] usb 1-1.4: New USB device strings: Mfr=2, Product=3, SerialNumber=1
[    5.237500] usb 1-1.4: Product: BUP Slim BK
[    5.277833] usb 1-1.4: Manufacturer: Seagate
[    5.284450] usb 1-1.4: SerialNumber: ********
[    5.324772] usb 1-1.4: The driver for the USB controller dwc_otg_hcd does not support scatter-gather which is
[    5.370438] usb 1-1.4: required by the UAS driver. Please try an other USB controller if you wish to use UAS.
[    5.417744] usb-storage 1-1.4:1.0: USB Mass Storage device detected

This is the message that caught my attention:

The driver for the USB controller dwc_otg_hcd does not support scatter-gather which is required by the UAS driver. Please try an other USB controller if you wish to use UAS.

I did a Google search and couldn't find out what it means. Is this bad? Am I going to be able to use this hard drive?

Any help on this matter would be appreciated.

  • What do you get when you run sudo blkid – jslay Feb 20 '15 at 22:05
  • I get /dev/mmcblk0p1: SEC_TYPE="msdos" LABEL="boot" UUID="140A-14B7" TYPE="vfat" /dev/mmcblk0p2: UUID="f24a4949-f4b2-4cad-a780-a138695079ec" TYPE="ext4" – Jody Heavener Feb 20 '15 at 23:50
2

This article helped me get it going. Specifically the part about enabling the 1.2A current limiter using:

max_usb_current=1

That information, along with ppunkin's suggestion of upgrading the Raspbian Jessie helped me get the hard drive running properlly. It now shows when I sudo fdisk -l.

0

This seems to be a Raspberry Pi 2 specific... but also new kernel to support armv7 that only occurs with specific models of the Seagate drives.

You have a two options really:

  • in /boot/cmdline.txt add the line, or change it if its there to: rootdelay=5 or rootdelay=10 (Causes a delay for USB to initialise)
  • Upgrade to Jessie (Likley due to the fact that systemd is now used)

The problem seems, at least on the Pi2 that some events go allot quicker now and are not triggering properly, or these specific models of HDD take longer to initialise.

*Source

  • My cmdline.txt already has rootwait - I assume that gets removed in favor of rootdelay? – Jody Heavener Feb 21 '15 at 1:53
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    Yea, DONT do rootwait=5, DO rootdelay=5 – Piotr Kula Feb 21 '15 at 1:55
  • Hmm, rootdelay didn't seem to do it - beginning the long process of upgrading to Jessie (using these instructions) (I should do that anyway, shouldn't I?) – Jody Heavener Feb 21 '15 at 2:33
  • You might have some issues installing certain packages. I did this about 18 months ago and had some issues. But it seems like people are doing now anyway. Everything seems to be in Jessie now. Its only a trial and error. Sorry that the delay thin didn't work :( – Piotr Kula Feb 21 '15 at 2:35
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    Did you try with a powered USB hub?? :) – Piotr Kula Feb 21 '15 at 10:13

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