Re: UNS: Re: [Xen-devel] BAR 0: cirrusfb load errors prevent hvm domu from getting resolutions above 800x600

["Jan Beulich" <JBeulich@xxxxxxxx>]

>>> On 17.11.11 at 09:31, jim burns <jim_burn@xxxxxxxxxxxxx> wrote:
> On Thu November 17 2011, 8:10:08 AM, Jan Beulich wrote:
>> >>> On 17.11.11 at 00:28, jim burns <jim_burn@xxxxxxxxxxxxx> wrote:
>> Sounds more like a kernel problem.
>> 
>> > <4>[    0.629101] vesafb: cannot reserve video memory at 0xf0000000
>> 
>> This doesn't tell what component did the reservation before this point,
>> but that's what he/you will need to find out. And then compare with
>> the cirrusfb case.
> 
> I thought that's what this meant:
> 
> [    0.667812] vesafb: framebuffer at 0xf0000000, mapped to 
> 0xffffc90000580000, using 1875k, total 4096k
> 
> Looks like vesafb reserved it.

No - the absence of the former message means it reserved it. But its
presence does not provide information on what, in that case, managed
to reserve it before. But that's what you want to hunt down.

>> One significant difference of course is the DRM base fb driver in the
>> radeon case - to compare apples with apples, DRM should really be
>> removed from the picture.
> 
> True. I was just pointing out that there is a mechanism for vesafb handing 
> off 
> control to another video driver:
> 
> <3>[  259.974310] fb: conflicting fb hw usage radeondrmfb vs VESA VGA - 
> removing generic driver
> 
> Any ideas where to go from here? Thanx.

You could have looked at this easily yourself - cirrusfb_register() (which
is what calls register_framebuffer(), which is where above message
originates from) gets called from cirrusfb_pci_register() only *after*
that function tried to reserve its resources via pci_request_regions().
(This is in 3.2-rc2, so even the most current driver isn't capable of
doing this sort of handshake, and afaict that's no different on native,
so not a Xen issue at all.)

Btw., looking at the title again - I don't think you need cirrusfb to
get higher resolutions, at least not if you're talking about X (only if
you merely care about the text consoles this would be the case),
as long as a respective X driver is present.

Jan


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