X11 server Virtual Desktop Support

[Keith Roberts]

On Mon, 1 Sep 2008, Adam Jackson wrote:

> To: For testers of Fedora Core development releases
>     <fedora-test-list at redhat.com>
> From: Adam Jackson <ajax at redhat.com>
> Subject: Re: X11 server Virtual Desktop Support
> 
> On Sat, 2008-08-30 at 20:14 +0100, Keith Roberts wrote:
>
>> ... I seem to have got the idea from somewhere that the
>> virtual keyword is not supported in xorg.conf anymore. I
>> think it was from a post on another mailing list where I
>> found this link:
>>
>> https://bugs.freedesktop.org/show_bug.cgi?id=11418
>
> So, there's two things here.
>
> One is the Virtual keyword in xorg.conf.  At a base level, all that does
> is define how much video memory to reserve for the logical screen.  It's
> just a size.
>
> The second thing is what the driver does with that space.  There are two
> kinds of drivers, for purposes of this discussion we'll call them legacy
> and randrful.  Legacy drivers can, at their option, enable a panning
> mode, in which the Virtual size defines the size of the root window, and
> the current cursor position is used to pan a viewport onto that root
> window.  In randrful drivers, that functionality simply is not present.
>
> (This is made slightly more confusing in the nv driver because it
> manages to be either legacy or randrful, depending which kind of chip
> it's driving.  G80 and newer chips - GeForce 8xxx and newer - are
> randrful, and earlier are legacy.)
>
>> BTW - is this the same X11 server code that Fedora uses?
>> There seems to be more than 1 version of the X11 server code
>> available for downloading.
>
> Yes, it is.
>
>> I have tried changing the above F9 Section "Screen" to:
>>
>> Section "Screen"
>>          Identifier "Screen0"
>>          Device     "Videocard0"
>>          DefaultDepth     24
>>          SubSection "Display"
>>                  Viewport   0 0
>>                  Depth     24
>>                  Virtual 800 1800
>>                  Modes    "800x1800" "800x600" "640x480"
>>          EndSubSection
>> EndSection
>
> That "800x1800" line in the Modes line isn't going to do what you want.
> A Mode in the config file is a description of the region to display and
> the timings of the synchronization regions at the edges.  You don't
> _want_ to display 800x1800.
>
>> But the font sizes are *way* to large. This is why I'm still
>> using F8.
>
> Which sounds like we're just computing the dpi from the Virtual size
> instead of the default mode size.  Merely a bug, but again, need to see
> the log from the broken configuration to know for sure.
>
>> The Xorg.0.log file (using startx -- -logverbose) tells me:
>>
>> '''
>> (WW) No monitor specified for screen "Screen0".
>>          Using a default monitor configuration.
>> '''
>>
>> I think I need a Monitor section in the F9 xorg.conf to set
>> the font size with the DisplaySize keyword. I'm not sure how
>> to go about adding the Monitor section to the F9 xorg.conf
>> to implement this. Any suggestions would be greatly appreciated.
>
> Section "Monitor"
>    Identifier "Monitor0"
>    # any settings you want...
> EndSection
>
> Section "Screen"
>    Identifier "Screen0"
>    Monitor "Monitor0"
>    # the rest of your Screen section as above...
> EndSection
>
> - ajax
>
Thanks for taking the time to explain all that Adam. I'll 
try your suggestions and see how they work out. As soon as I 
have some results I'll post again on this list.

Kind regards,

Keith Roberts