setting up xorg.conf

[Carl Karsten]

(recovering from cross post fumble... nothing new for the Ubuntu list, 
just getting both lists in the loop.)

Daniel Stone wrote:
> On Tue, Apr 12, 2005 at 12:47:40PM -0500, Carl Karsten wrote:
> 
>>xorg guys have some interest in something that I thought I had seen here 
>>but I can't find it.  Also, anyone leaning on ddcprobe may be interested 
>>in what I found.
>>
>>google ddcprobe:
>>
>>http://cvs.seul.org/cgi-bin/cvsweb-1.80.cgi/distrib/install/anaconda/ddcprobe/README?rev=1.1.1.1&content-type=text/x-cvsweb-markup
> 
> 
> This is the source our ddcprobe is based off, yes.
> 
> 
>>https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=138381 "ddcprobe 
>>claims to do a "Videocard DDC probe". However, in the course of 
>>troubleshooting bug 108681, I learned from Mike Harris that there is no 
>>such thing.  I think it would be less misleading if it was called 
>>something like a "Videocard VBE probe". Even if that's not the best 
>>phrase either, it's much better and much closer to the truth than 
>>"Videocard DDC probe".
> 
> 
> 'VBE probe' is rather meaningless -- what it should really say is 'VBE
> DDC probe', but hopefully that won't be true for too long.  As that bug
> says, DDC is a generic name for describing the sort of probe that gets
> done.  VBE is one way to do it.  Doing it by setting up I2C channels and
> poking them in specific ways is another way to do it.  We do the former.
> 
> 
>>CarlK: it seems a common problem is getting the valid resolutions in 
>>xorg.conf
>>CarlK: valid = ones that will work with my hardware (video card, video 
>>memory and monitor)
>>ajax: if we had a way to probe DDC on a card without running all of X, 
> 
>                            ^^^^^^^^^^^^^^^^^^^
> 			   he means via I2C channels
> 
>>we could do that pretty reliably
>>ajax: linux might give you enough info through sysfs to make that possible
>>CarlK: ever heard of ddcprobe?
>>libv: CarlK: that most likely uses VESA
> 
> 
> It sure does.
> 
> 
>>CarlK:  /usr/sbin/ddcprobe - can't figure out where it comes from - no 
>>man or info
> 
> 
> Comes from the xresprobe package.
> 
> 


> On Wed, Apr 13, 2005 at 01:21:58AM +0100, Matthew Garrett wrote:
>>> On Wed, 2005-04-13 at 10:08 +1000, Daniel Stone wrote:
>>
>>>>> > > libv: which makes it a BIOS dependant function, which only makes it 
>>>>> > > possible on the primary graphics card
>>>
>>>> > 
>>>> > Yeah, which sucks.
>>
>>> 
>>> This bit can actually be solved without too much pain (a-ha ha ha) -
>>> it's a "simple" matter of reading the ROM off the secondary cards,
>>> setting up the PCI legacy video IO routing and then executing the code
>>> in it. Jon Smirl's been working on this sort of thing.
> 
> 
> Right, but screwing around with PCI routing is so very nasty.  Last I
> checked, you had to disable the IO routing for the primary card, then
> walk the series of bridges, setting a specific VGA routing flag, then
> enabling IO routing for that specific card.  If it gets done in the
> kernel such that we can rather transparently cat the BIOS out of /sys,
> more power to Jon.  I've certainly got no desire to do that in
> userspace.


> 
>>ajax: probably the easy solution is to bump the default resolution to 
>>800x600,
> 
> 
> No thanks.
> 
> 
>>use DDC by default
> 
> 
> Um, we already do.
> 
> 
>>and cache the results of the DDC probe from the last server startup
>>ajax: that last bit being important, so the monitor still works even if 
>>you start X with it powered down.
> 
> 
> Yeah, I've been meaning to get to that for a while.  Bug#5917.

https://bugzilla.ubuntu.com/show_bug.cgi?id=5917

> 
> 
>>JakubS_: so there should be no problem with only primary card - from 
>>what i have seen there is bios image for video card in /sys
>>JakubS_: it would probably have to be run on emulator, like x server does
> 
> 
> On i386, it runs natively.  On powerpc, it's exposed via /proc.  On
> amd64, ia64, hppa and sparc, it doesn't run at all.  But eventually, it
> will be run on an emulator (x86emu) like X does - Bug#1421.

https://bugzilla.ubuntu.com/show_bug.cgi?id=1421

> 
> 
>>If someone can give me the subject(s) of the ubuntu threads (pretty sure 
>>it was here) I'll forward it to xorg at lists.freedesktop.org
> 
> 
> Which Ubuntu threads?
> 

Apparently only this one ;)

Carl K