RV770: Ubuntu hangs on X start

[d2kx]

Hi,

for some reason Ubuntu 8.10 and 9.04-daily hang when I try booting the desktop CDs at the time when X starts. I did an alternate installation and it installed fine (of course) but then when X started after installation it hang again. But now I had the chance to boot without X and surprisingly there was no Xorg.0.log. When I installed the proprietary Catalyst driver it worked...

My system:
AMD Phenom II X4 940
MSI 790GX/SB750 based
ASUS Radeon HD 4850 1GB

The interesting note is that Debian works fine, even with older versions! And there's a big difference between Ubuntu 8.10 and 9.04-daily and still the same issue.

Anyone has an idea?

- d2kx

[Kano]

I think you have got onboard vga, just remove your pci-e card (if you think it is the problem). There are some hacks possible like

nohz=off

which might help.

[MU_Engineer]

I think you have got onboard vga, just remove your pci-e card (if you think it is the problem). There are some hacks possible like

nohz=off

which might help.

The 790GX does have onboard VGA, but I would think that since he has a Radeon 4850, he'd want to use that instead of the Radeon 3300 IGP. Usually people who have an IGP and a discrete card will go into the BIOS and deactivate the IGP when using the discrete card. However, IGP vs. discrete issues tend to manifest as "no picture at all when I am connected to $ONE_OF_THE_CARDS" rather than X hanging...especially when he gets it to work fine with fglrx.

@d2kx:
My guess is that Ubuntu 8.10/9.04 is using a recent xserver-xorg-video-ati as the driver for your card that has 2D support for the R700 cards like your 4850. Ubuntu also enables Compiz by default, which won't work on R700 cards due to a lack of 3D support in the current ati driver, but Compiz WILL work with fglrx on those cards. That could very well hang X unless you install fglrx. Debian most likely works because it not only doesn't set up Compiz by default (which means that you're only using 2D) but probably also uses vesa as the display driver, which works no matter what card you have.

If you want to test my hypothesis, install fglrx in Ubuntu so you can get to X and then turn off the desktop effects. Then change the driver line in xorg.conf to "radeon" and make sure you modprobe drm and radeon, then restart X. If I am right, it should magically work and X should *not* hang.

[Kano]

Usually the onboard vga is off when you plug in a PCI-E card, if you disable it completely then you don't do yourself a favour when you have to remove the PCI-E card. But as this could be an x problem, the vesa override for ubuntu is just:

xforcevesa

for the live images. Btw. my fglrx script works up to 8.10 in live mode too

[d2kx]

Okay, booted with "xforcevesa" cheatcode, installed and then installed RadeonHD and used that. Works

Weird that Radeon has failed for me... Radeon also always had problems with VT switching when KDE wasn't running or when shutting down. Oh well, I love my RadeonHD even if doesn't support too much for RV770 yet

[hmmm]

agd5f mentioned that hanging issues on all rs7XX chips have been recently been fixed, ( http://www.botchco.com/agd5f/ ) :

For those of you with rs780 chips wanting to try the new EXA/Xv accel, I’ve sorted out the hanging issues. You’ll need the latest bits from the r6xx-r7xx-accel branches of both the drm and radeonhd. I’ve also fixed a hang on r7xx chips due to the way you have to do SQ constant updates; this may help rv670/680 users as well.