Re: 2.6.38-rc7/rc8 no output on VGA under xen

[Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>]

On Tue, Mar 15, 2011 at 06:08:48PM +0100, Andreas Olsowski wrote:
> After another day of testing i have not managed to get this working.
> I even tried totally different hardware, the console stays dark.

And what is the lspci off the different hardware? What is the
diff between the original hardware and this hardware?

> The blinking cursor i only get when i am starting with serial console.

And you did follow the PVOPS Wiki on troubleshooting and using
"console=hvc0 debug"
> 
> So output is possible, its just not done.
> 
> Is 2.6.38 somehow incompatible with the hypervisor?

No. The issue is (and I explained this to you on irc) is that the video
driver you have is an PCI/AGP type. The patchset to make the 2.6.38
(devel/agp.pci-api) haven't been up-ported to the 2.6.38 tree. In essence
the code to make this work is not there. The 2.6.32 has this code.

> 
> Today on irc someone said he had the same problem with 2.6.37.

Uhh.. yeah that is expected. There are no patches in the 2.6.37 tree
to make it work.

> 
> Please tell me if you are experiencing the same problems or if you
> dont, please send me a link to your kernel .config.

You got three options:
 - Stick in a PCI-e discrete graphic card. Say Radeon el-cheapo. See how
   that works.
 - Make sure to disable the MGA driver from the kernel and only use
   the VESA/VGA framebuffer. That _should_ be working. If it is is not
   please send an e-mail here.
 - Back-port yourself the #devel/agp.pci-api in the 2.6.38 kernel.
   There is going to be a compile fallout somewhere in the drivers/gpu/drm/intel,
   but you could patch that over by just passing a NULL pointer.

My .config is basically using the Ubuntu 11.04 config will XEN_ options turned
into =y. But that won't help you in this case.