Unable setting resolution

[mlager]

Goodday to all of you,

Currently I'm experiencing something rather annoying on my laptop. At the moment I got it installed as a dual-boot system with FC6 on one partition and Ubuntu on the other. For some dark, obscure, and I'm sure evil as well reason I can't set the resolution.

I'm trying to set it to 1024x768, which is its highest resolution. In the GUI I select the generic LCD monitor, set the right resolution. To be sure I take a look at the xorg.conf, and I think: "Victory!"
All is set as it should be, so I reboot.

When it start up again, it's still set at 800x600. So once logged in I go to Preferences / Screenresolution.
Only options are 800x600 or 640x480.
So I check the xorg.conf, and everything is as it was last time I checked:

Section "Monitor"
	Identifier   "Generic LCD Monitor"
	Option	    "DPMS"
EndSection

Section "Device"
	Identifier  "ATI Technologies, Inc. Radeon Mobility M6 LY [Radeon Mobility 9000]"
	Driver      "radeon"
	BusID       "PCI:1:0:0"
EndSection

Section "Screen"
	Identifier "Default Screen"
	Device     "ATI Technologies, Inc. Radeon Mobility M6 LY [Radeon Mobility 9000]"
	Monitor    "Generic LCD Monitor"
	DefaultDepth     24
	SubSection "Display"
		Depth     24
		Modes    "1024x768" "800x600" "640x480"
	EndSubSection
EndSection

So why don't I get my precious 1024x768 resolution? Does some have an idea on what I am missing? Clearly, unless you are as visually challenged as three blind mice you don't really want 800x600 resolution.
Any help would be welcome.

Mark

btw. If I boot with Ubuntu it starts just fine in the right resolution.

[stevea]

I had a similar problem with a mobility radeon M10 in laptop. When I looked in the X11 log files
(/var/log/Xorg.0.log) is seems that the Xorg radeon driver attempted to read the horizontal (and vertical?) sync frequency range from the interface and decided that I would not be allowed to use the "correct" resolution but would have to settle for 800x600 (my display is 1400x1050).

I used an old (FC5) xorg.conf file as a pattern and manually edited my /etc/X11/xorg to include the HorizSync & VertRefresh as ....

Section "Monitor"
Identifier "Monitor1"
VendorName "Monitor Vendor"
ModelName "LCD Panel 1400x1050"
### Comment all HorizSync and VertSync values to use DDC:
HorizSync 31.5 - 90.0
VertRefresh 59.0 - 75.0
Option "dpms"
EndSection

Also I added the correct "Modes" at that time.

Modes "1400x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600"

===
Many paths were searched to solve this one, so I hope I have characterized the solution correctly.

[mlager]

That might work. Only one little problem though, I wouldn't have a clue what the horizontal sync and the vertical refresh rates are. It's an oldish laptop, and I wouldn't know what the specs on the LCD are. Is there a way to determine that? Tried googling for the specs, but no succes

[stevea]

I believe the HorizSync & VertRefresh rates are hardware design dependent and that *perhaps* the recent xorg driver is not getting the correct values. You are probably safe with the Vertsync listed, but ... the horiz is a bit of a guess. I'd personally try with a lower low end like:
HorizSync 20.0 - 90.0
You should see lines in /var/log/Xorg.0.org like ...

(II) RADEON(0): Panel ID string: SXGA+ Single (85MHz)
(II) RADEON(0): Panel Size from BIOS: 1400x1050
(II) RADEON(0): BIOS provided dividers will be used.
(II) RADEON(0): Total number of valid DDC mode(s) found: 0
(II) RADEON(0): Valid mode using on-chip RMX: 1400x1050
(II) RADEON(0): Valid mode using on-chip RMX: 1280x1024
(II) RADEON(0): Valid mode using on-chip RMX: 1280x960
(II) RADEON(0): Valid mode using on-chip RMX: 1152x864
(II) RADEON(0): Valid mode using on-chip RMX: 1024x768
(II) RADEON(0): Valid mode using on-chip RMX: 800x600
(II) RADEON(0): Total number of valid FP mode(s) found: 6
(--) RADEON(0): Virtual size is 1400x1050 (pitch 1408)
(**) RADEON(0): *Mode "1400x1050": 85.0 MHz (scaled from 0.0 MHz), 53.1 kHz, 50.0 Hz
(II) RADEON(0): Modeline "1400x1050" 84.96 1400 1472 1512 1600 1050 1052 1053 1062
(**) RADEON(0): *Mode "1280x1024": 85.0 MHz (scaled from 0.0 MHz), 53.1 kHz, 50.0 Hz
(II) RADEON(0): Modeline "1280x1024" 84.96 1280 1472 1512 1600 1024 1052 1053 1062

Which describe the accepted mode, or else you'll see the screen sized rejected.

==
Actually this is a mess. Perhaps you should select the VESA driver, and reboot, than update everything (yum update) and then see of the radeon driver works any better for you.

[mlager]

I'm pretty sure the computer is up to date, I usually make sure of that. With vesa I pretty much run into the same thing, with one difference; I can set the resolution to 1024x768 with display-resolution GUI. But it doesn't hold it's setting. After a reboot I have to reconfigure again.

[jim]

I have 3 pc's running fc6 and all of them I cannot change the display settings

notebook 1024X768 <--- fine

Desktop1 1280X1024 <--- too small for my wifes eyes

Desktop2 800X600 <--- too big rather see 1024X768

i can change it in system config display log out and back in no change