I think, almost everybody, who has an AMD/ATI graphics card, has already heard about the new RadeonHD Linux Driver, but not everyone has already tested it.
For my part I'm testing since yesterday and the whole thing is growing very fast, however I do not yet have a proper output on my Mobility Radeon X1400. But this is not what I wanted to write here, I wanted to write how to help the developers.
First you need to send some beer, some peanuts and maybe also some money to libv (#radeonhd on freenode), then he might start looking on your reports g - sorry libv ;) just kiddin too ;)
1. get the driver
As the driver is in a very early stage of development, changes are made every day and packages from your distribution (well, I only know that Debian has it in it's repositories) is maybe outdated at the time of uploading by the maintainer, so please build it from git, as perfectly described here at phoronix.
2. test the driver
a) You get a picture when starting X with the radeonhd driver? Feel lucky and maybe write an email to firstname.lastname@example.org, telling the guys how much you love them, and what card works for you.
b) You get a black screen, but X has properly started? The driver has correctly recognized your card, but had problems to set-up correctly, please read on.
c) You get an error in your log, and no X? That might have several reasons, let's look in your log. Does it state something like
(WW) RADEONHD(0): Unknown card detected: 0x1234:0x1234:0x1234 (imagine some other numbers here)
(EE) RADEONHD(0): Cannot map connectors on an unknown card!
If so, your card could not be recognized, as every vendor (ASUS, Gecube, etc) might give the card a slightly different subsystem id, which is not yet known to the driver. Please have a look at reporting card info, so your card can soon be added to the driver.
Or do you probably get something like
(EE) RADEONHD(0): No valid modes found?
This should happen, when the driver could not get enough/correct information, what mode you monitor wants to run with, this does lead to the previously described black screen too (as I get it here at the moment). I do not think this should be reported at the moment, as the problem is known to the developers.
3. reporting card info
When you decide to report something (which is the real help-part here), you should do it correctly.
First you should describe what card do you have (not only Radeon X1950, but ASUS FunkyNameOnTheBox Radeon X1950), and what result do you get (working X, not working X, X not finding something, etc).
Then attach your logfile (usually it's /var/log/Xorg.0.log), but don't forget to compress it before, this really saves traffic.
The last one is probably the most important one: the conntest output (see below).
conntest is a small tool which probes the connectors of the video card.
You can find it in utils/conntest/ in git, and build it just by calling make (dont forget to install pciutils-dev).
The you call it with ./rhd_conntest <pci tag> as root, where <pci tag> is the number lspci shows you in front of the name of your card - usually it is 01:00.0
But you should not run it just once, but for every output your card have.
On a laptop it's usualy once with nothing attached (only internal screen is active), and once with a screen connected to the VGA port.
If your laptop has a DVI and not a VGA connector, please run rhd_conntest once for a analog screen connected through an DVI-VGA adapter, and once for a digital DVI-connected screen.
On a desktop, you would call it once for NO screens connected, and then same as for a laptop: once with a analog screen on each VGA connector and then once with an analog screen with a DVI-VGA adapter and once with a digital screen on each DVI connector.
Have a look at the README in the same dir, it describes everything a bit more.
As soon as you have all the data you want to share, send the mail to email@example.com and wait for a reply.
I hope this can help somebody to get his card working with RadeonHD