Can you put the following in your rc.conf:

MODULES=(ehci_hcd uhci_hcd ohci_hcd)

And see if that solves the problem?

Well, this does not solve the problem. I still have to wait 40 minutes until the hard drive gets mounted. The most frequent line changed to "hub 1-2:1.0: unable to enumerate USB device on port 1". See also dmesg output.

I don't know if it helps, but when I'm just rebooting or switching the computer for a short period of time of the hard will be recognized regulary.

Can you rmmod all USB modules, and modprobe just ehci_hcd, and then plug in your device and see if it works?

No, this doesn't work for me. I removed ehci_hcd uhci_hcd ohci_hcd and loaded just ehci_hcd, but it didn't help. I'm still getting a lot of these lines "hub 1-2:1.0: unable to enumerate USB device on port 1". I've also tried to unload usb_storage and usblp, but there is no change.

The same problem occured on http://bugs.archlinux.org/task/11289, and was solved by loading ehci first. Are you sure ehci gets loaded first? Can you post your dmesg with the changes you've made recently? Did you reboot after modifying the MODULES line in rc.conf?

MODULES=(ehci_hcd p4-clockmod cpufreq_ondemand uhci_hcd ohci_hcd) this is what I've entered into rc.conf. After reboot it seems that ehci_hcd gets loaded correctly before the other usb modules (see dmesg3.txt). Well, but it always worked for me when the hard drive was recognized in before. So let's wait some hours with power off and see if it is really working.

I've just switched on my computer and external hard drive and I'm still waiting for it to be recognized. I think that you can't compare an USB charger with an external USB hard drive. You have to distinguish between the problem of the USB charger (also known when e.g. plugging a usb mouse into my EEE-PC with Debian/Testing) and my external hard drive. Any more suggestions?

Are you running "Ubuntu 8.10" and Arch Linux in the same machine?

I don't see such problem in my PC (very similar to yours). Last week I plugged an external USB drive (USB powered), I had power problems (unrelated to OS) but the drive was correctly detected in no time.

Last time I saw "unable to enumerate USB device on port n" it was a hardware problem; make sure your USB card is correcly inserted or try to use another PCI slot. This may really help.

My snipped lspci output:
00:00.0 Host bridge: Intel Corporation 82845 845 [Brookdale] Chipset Host Bridge (rev 03)
00:01.0 PCI bridge: Intel Corporation 82845 845 [Brookdale] Chipset AGP Bridge (rev 03)
00:1e.0 PCI bridge: Intel Corporation 82801 PCI Bridge (rev 12)
00:1f.0 ISA bridge: Intel Corporation 82801BA ISA Bridge (LPC) (rev 12)
00:1f.1 IDE interface: Intel Corporation 82801BA IDE U100 Controller (rev 12)
00:1f.2 USB Controller: Intel Corporation 82801BA/BAM USB Controller #1 (rev 12)
00:1f.3 SMBus: Intel Corporation 82801BA/BAM SMBus Controller (rev 12)
00:1f.4 USB Controller: Intel Corporation 82801BA/BAM USB Controller #1 (rev 12)
02:02.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 62)
02:02.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 62)
02:02.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 65)

I've tested Ubuntu 8.10 with the live cd as also Fedora 10. Both worked without any problems with my external hard drive. The power supply unit seems fine as it also worked with my Eee-PC.

I've removed all pci cards and put the usb card in every single slot and tested it, but in all cases I've got the same error. Any further ideas? From my point of view, the hardware works well. So I'm still thinking that this is a software problem or my DELL machine doesn't want to work the way I want. Ubuntu is probably more tolerant towards hardware/software problems, but Fedora also worked out of the box with the live cd.

What I did not mention is, that the build in card reader of the external hard drive works fine.

Assigning to people who know this topic better than I.

Do you guys have any advice? Is this a hal or a udev issue?

From what I can see, this is definitely a kernel issue, udev or hal are not involved until the device is added and scanned properly.

@Martin: Can you provide us with kernel versions for working OSes (Ubuntu, Fedora, etc) and the kernel versions on Arch which have failed you (has it been ALL kernels?)

Concerning Arch, I can tell you that this problems occurs to me since Kernel version 2.6.25.11 or in other terms since I installed Arch in late July 2008. I've written in the german forum post that it worked with 2.6.25.11 in case I switched on the hard drive, switched off and again on. But this was in September and now I'm not really sure about this. I have the old kernel packages still on my hard drive so that I could test this again. How does affect loading the usb modules in the correct order manually by rc.conf this whole thing because I never did this during my tests before.

It worked fine with an old Kernel version 2.4.20 of a Knoppix live cd. Probably, chances are better that it will work with Kernel version <=2.6.24 as most people have reported this.

It also worked fine with following OSes:

* Fedora 10 (2.6.27.5)
* Ubuntu 8.10 (2.6.27.7)
* Suse 11 (2.6.25.5)

What I cannot understand is, why my external hard drive works fine after a reboot when it was recognized in before.

This is getting more and more strange. The hard drive is not recognized after a cold start with Fedora 10, Ubuntu 8.10, Suse 11 as also Ubuntu 5.10 with kernel 2.6.12.9, but USB 1.1 works fine. With Ubuntu 5.10 I'm getting a lot of these "Maybe the USB cable is bad" lines in dmesg's output. But with Knoppix 3.2 (Kernel 2.4.20) it is recognized after cold start. Also cold start with my EEE-PC is not working which gives me the same error as Arch.

I think it would be helpful to reinstall the usb pci card with ALI chip set and test it again.

Can you try with another USB device? Like an USB stick, mouse, etc...

Several USB sticks, a USB printer, a USB mouse and a USB GPS receiver work fine with my USB 2.0 pci card.

So only your external harddisk is giving this "unable to enumerate" problem?

Yes, this is correct. Just the external hard drive, everything else work without any problems. I don't have any other external hard drive to test.

Looks like we should blame TrekStore here... maybe you could do some googling and see if anyone has patches related to trekstore or similar devices?

There seems to be a problem with the module 'ehci_hcd'. The only workaround I know is to rmmod ehci_hcd, switch on the hard drive, wait sometime and modprobe ehci_hcd. Then, I get USB 2.0 support. I'm not really happy with this solution as you could imagine.

In fact, the problem seems to be with the internal chip set of the hard drive (Prolific Technology, Inc. PL2507 Hi-speed USB to IDE bridge controller) which needs some time to work with USB 2.0. I've read many posts on the internet about people complaining that their TrekStor hard drive is not recognized under Windows. My conclusion is that the problem is inside the externel hard drive. Probably with hard drive from Hitachi is fine, but the internal chip set is broken. Cold start only works for me under Kernel version 2.4. As other USB devices work without any problems, the problem should not be caused by the pci card.

I don't know if there is a kind of patch for this module or the kernel.

what is the current status of this issue with the current kernel 2.6.29.4?

I can't tell you about the current status as I returned my old Trekstor hard disk to the dealer in December. At the same time, I bought a new external hard disk from Western Digital which works absolutely fine. Probably my Trekstor hard disk was internally damaged because of the heat which it produced.

Ok thanks for response, so can request closure this ticket.

This is happening to me too with a Freecom Mobile 120GB USB hard drive.

Kernel version: 2.6.31-ARCH

any news on this with latest kernel26?

Still produces the following dmesg output constantly for about half an hour before finally mounting the device...

hub 1-0:1.0: unable to enumerate USB device on port 4

Kernel Version: 2.6.32-ARCH

is there any references to upstream? If not, please report to http://bugzilla.kernel.org. Because I think that we can't do much nothing here without help from kernels devs.