Accepted xresprobe 0.4.24ubuntu1 (source)

Timo Aaltonen tjaalton at
Thu Mar 15 14:54:59 GMT 2007

first of all, sorry for taking so long to reply.

On Sat, 10 Mar 2007, Matt Zimmerman wrote:

> On Thu, Mar 08, 2007 at 12:14:05PM +0200, Timo Aaltonen wrote:
>> On Wed, 7 Mar 2007, Matt Zimmerman wrote:
>>> Does this provide us with any useful information?  Does the VESA BIOS
>>> accurately report the size of an attached LCD?
>> No it doesn't, but the server autoprobes the best values it can use.
> How does it probe this when it's using the VESA driver, if not by way of the

Those are two different things :) The panel can be a gigantic widescreen 
which the vesa-driver can't drive with it's native resolution. Then the 
driver would use the best mode the BIOS has. In the case of TP Z61p which 
has a 1920x1200 capable panel it would use 1600x1200.. stretched but 
better than 1024x768.

> We should only be changing this part of the infrastructure at this point in
> the release cycle in very well-defined and predictable ways, and hardware
> detection is especially tricky.  The change should definitely be limited
> to cases known to be handled incorrectly if that is possible, and they
> should also be scrutinized to ensure that they're improving the situation.

Right, so limiting the autoprobing to vesa is ok?

> Again, can you describe the problem this change is meant to solve?  Are
> there bug reports which are relevant to this problem?  How did you decide to
> make this change?

I've been trying to find the bug but can't... At least all radeon r5xx 
chip owners are affected, but also others where the panel allows a better 
resolution than 1024x768 and the driver used is vesa (for one reason or 

The problem in a nutshell: previous xresprobe probes some settings running 
X with a barebones xorg.conf (with 1024x768 resolution) and then greps 
some values from the resulting log. Since the vesa-driver cannot identify 
the panel and it's dimensions, the resulting xorg.conf always uses 
fallback resolution which is 1024x768. And that is what the change in 
xresprobe is trying to fix.


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