[ltp] Brightness and Suspend on T61 6459-CTO

[Marius Gedminas]

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On Tue, Nov 06, 2007 at 09:04:44AM -0800, John Jason Jordan wrote:
> On Tue, 6 Nov 2007 10:44:22 -0500
> Mike Kershaw <dragorn@kismetwireless.net> dijo:
>=20
> > I still haven't solved the problem where the external USB ports don't
> > resume properly but the internal USB system (fingerprint and bluetooth)
> > does, if anyone has any thoughts on that one (usbcore suspend doesn't
> > seem to affect it, nor does unloading or not unloading the modules, and
> > it seems to happen from at least 2.6.22 through 2.6.24rc1-wireless-git)
>=20
> I'm just a desktop user and I know little of how these things work,
> plus I'm still pretty new to Linux. But I have noticed a problem with
> my T61 that did not happen with my old computer running Feisty and the
> problem may be related to this issue.
>=20
> I use a Logitech external wireless notebook mouse that has a small USB
> receiver (about the size of a thumb drive). My old computer with Feisty
> had three USB ports and I could hot-swap the receiver into any of the
> ports and the mouse continued working without a problem. On my new T61
> with a fresh install of Gutsy amd64 I usually put the receiver in the
> bottom USB port on the back right corner. But if I move it from that
> port (e.g., to the port in the middle of the left side) it will
> continue to work in the new port, but won't work if I later move it
> back to either of the ports on the back right corner. From that point
> it will only work in the port in the middle of the left side until I
> reboot. In fact, those two ports are completely dead until I reboot -
> for example, they don't work with my thumb drive either.

This is a bug with the T61 (and X61) that nobody knows how to fix.
About ten minutes (but sometimes fifteen, and sometimes a lot later)
after a reboot the kernel gets an IRQ (sometimes it's IRQ 21, sometimes
23, sometimes 19) that is not claimed by any driver.  You get a scary
message in your dmesg, the kernel disables that IRQ, and after that the
two USB ports on the right side nearly stop working.

I say "nearly" because any USB device that was plugged in at that time
continues to work.  Newly plugged in devices don't work, but if you
leave them plugged in for a long time (about ten minutes?), they
are eventually detected and start working.

I've heard that you can fix this (temporarily, I assume) by unloading
and reloading the ehci_hcd module.

The Ubuntu bug about this is here: http://launchpad.net/bugs/126369

The kernel bug about this is here:
http://bugzilla.kernel.org/show_bug.cgi?id=3D8853

Marius Gedminas
--=20
When I'm not in my right mind, my left mind gets a little crowded.

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