[Xen-users] Re: Using pciback to dynamically bind/unbind primary display driver: lost console, help

Ben Himberg
Sat, 29 Oct 2011 02:14:05 -0000

Turns out I passed "dynpm" to radeon/power_profile instead of
radeon/power_method and it crashed atom bios (kept locking, timing out in
the error log).  Works fine now.  How do I control, on the fly, where kernel
output goes though?

On Fri, Oct 28, 2011 at 9:35 PM, Ben Himberg <bhimberg@gmail.com> wrote:

> On Debain 3.1.0-rc7, Radeon 6870 and Xen 4.1 (no patches)
>
> I used
>
> echo -n 0000:01:00.0 > /sys/bus/pci/drivers/radeon/unbind
> echo -n 0000:01:00.0 > /sys/bus/pci/drivers/pciback/new_slot
> echo -n 0000:01:00.0 > /sys/bus/pci/drivers/pciback/bind
>
> to move my primary display adapter (01:00.0) to pciback for domU use.  The
> display, as expected, turned off.  I had enabled ssh to do this, and have
> access to the system still.  I then used
>
> echo -n 0000:01:00.0 > /sys/bus/pci/drivers/pciback/unbind
> echo -n 0000:01:00.0 > /sys/bus/pci/drivers/radeon/bind
>
> to pass it back to dom0 at which point the display turned back on.
> Thinking all was well, I made a script to do the above and executed it
(with
> a sleep of 10 seconds after the first bind) at which point I lost the
> display, as expected, but it didn''t come back.  I then logged in
through ssh
> and find that the radeon driver is bound to 01:00.0, but still no display.
>
> I think I need to tell the console to output to the radeon driver, but I
> have no idea how and a google search is proving fruitless.  Any help?
I''ve
> also noticed that unbinding/binding the radeon driver is now (it
wasn''t
> initially) very slow to respond.
>
> Thanks!
>