Using the new import of Dave Airlie's Radeon KMS DRI driver, my laptop screen (LVDS-connected) goes blank and stays blank while using KMS and modeset=1.
Chip is a Modility Radeon X700 in a MSI Megabook M635 (also known as MS-1029) with a Turion 64 chip running X86-64 userland from Ubuntu (in particular, Karmic Koala and Kubuntu KDE4). I build my own kernels from mainline to test and will attach dmesg output, Xorg.0.log output (which also apes the Kernel's can't inability to find the LVDS connector -- don't be confused, I'm not complaining about X.org here), and dmesg output. r4xx_atom does not need to be forced: from reading the source and logs, the chip is identified as ATOMBIOS.
In my own disgnosis, I found that there is a quirk that matches this notebook in driver/gpu/drm/atombios.c but it is not used. Also, the drm.debug=1 option shows that the VGA and LVDS connectors are identified but no connector is assigned to the LVDS encoder, which I believe is why the screen is blank.
This is probably a dupe of bug 13683. r4xx_atom is still a valid option to try. While r4xx cards have an atombios that atom command tables are not used for programming the mode unless the r4xx_atom option is set. Please attach your dmesg with the debug option set for the drm module.
I don't think it's a dupe of that because the reported experience differs: I see no mouse cursor and no powersaving effects correct the lack of an image on-screen. A bit of googling indicates that my laptop has different hardware -- I'm using ATIIXP audio instead of a Via 82XX (see http://www.linlap.com/wiki/fujitsu+amilo+a1667g).
Created attachment 22233 [details]
dmesg output with r4xx_atom=1 set
Created attachment 22234 [details]
verbose lspci output
Created attachment 22235 [details]
.config file for kernel build used
can you attach your video bios?
echo 1 > rom
cat rom > /tmp/x700_vbios.rom
echo 0 > rom
Created attachment 22236 [details]
video bios file
Created attachment 22237 [details]
Fix quirk handling for MSI laptop
This patch should fix the connector enumeration.
Created attachment 22241 [details]
Dmesg with working KMS output.
The patch Works For Me, against mainline commit 8e4a71. Thanks so much for the quick turnaround.
WFM SignOff: Ken Lewis.