Xorg 7.1 and Dell 2405FPW at 1920x1200

[probate]

I've had X running at 1920x1200 with an Nvidia 6200TC using the following mode line

[bemis]

my 2405fpw is taunting me from next to my desk right now, and i'm only xorg7.0 currently so i can't comment from experience quite yet - but i can say that when i had similar issues with my dual 2001fp set up i had to disable EDID tagging for the new nvidia driver in xorg7.0
hope this helps
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Y'know, somewhere along the line, my brain got wired directly to my fingers .. I'm not even consulted anymore in the decision making processes.
-bemis

[probate]

I still don't have an answer to this, but after much googling I think I understand what is happening. Here it is for the benefit of others. If I find the answer I'll post it here.

Bandwidth limitations on single-link DVI restrict it to about a 155MHz pixel clock. Beyond this dual-link DVI must be used. Normally, 1920x1200 at 60Hz would require a clock rate of about 193MHz, however the use of what is called reduced blanking saves bandwidth and it needs only 154MHz.

Reduced blanking shortens the blanking period that is used for fly-back. This is a CRT monitor thing - time is needed to swing the electron beam back for the next scan. Flat panel monitors don't need this, so most can operate on a reduced blanking interval requiring fewer clock cycles.

The mode line I am using I found after searching. I wasn't aware of it, but its a reduced blanking mode line, and it worked with Xorg <=7.0. Xorg 7.1 is now reduced blanking aware. There is some concern that using reduced blanking on a CRT monitor could damage it, so support for it is now off by default. Detection of whether a monitor supports reduced blanking or not is a bit dodgey, and it seems that Xorg thinks the Dell 2405FPW doesn't support it when clearly, it does.

If found mention of an Xorg "ReducedBlanking" boolean option for the Monitor section, but it doesn't seem to be recognised. Could this be something in the Gentoo ebuild?

[bemis]

which modeline are you using?
(mine are:

[probate]

I'm using the second modeline (see my first post). The first one is a non-reduced blanking modeline. It doesn't work for the reason I've already explained. Are you sure the monitor is running at 1920x1200?

After more fiddling with various Options and looking at the Xorg source code it seems that The "ReducedBlanking" option is required in 7.1 if a reduced blanking modeline is to be displayed (see the bug linked in the first post of this topic). Without it, Xorg won't accept the modeline. I've found the code that checks this, and it looks OK, yet when I try this option, but it seems to ignored.

To further deepen the mystery, under some circumstances, the message "Option ReducedBlanking will not be used" appears in the Xorg log. This message seems to depend on what other options are used. I'm at a total loss now. I don't have the time to try and debug the code. I think I'll have to go back to Xorg 7.0.

[ekutay]

Another victim here
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-- erol

[ekutay]

Add: Option ReducedBlanking solved it for me.
Sure, that you have added it to the monitor section of xorg.conf?
_________________
-- erol

[probate]

Yes, I have put the ReducedBlanking option in the Monitor section.

I tried to move to 7.1-r1 hoping it might be fixed, but its blocked by nvidia-glx. My attempts at working without nvidia-glx and at going back to 7.0 are rapidly turning into one big mess and I can't get an X server to run at all now. I think I'll have to uninstall Xorg altogether and go back to the stable tree.

I should add that this is on an AMD64 system, compiled in 64-bit. Perhaps it has not been ported to 64 bits properly.

[ekutay]

Ah, just read the NVIDIA in your log statement. I'm not using nvidia but nv. Have you tried this one too?
_________________
-- erol

[probate]

OK. Tried using the nv driver rather than the nvidia, and it seems to work. The screen comes up in 1920x1200. Problem then is that XGL doesn't work. This post tells the whole story.

It sounds like a new nvidia driver that can be used with Xorg 7.1 is not too far away.

[kiboko]

I have a dual Dell 2405FPW setup on two workstations, (one with two MSI GT6800GT video cards, the other with only one). The monitors are attached via the D-SUB connector(s), (on the one card system , the D-SUB and a DVI-DSUB adapter for the DVI port). The workstations are hooked-up via a Belkin dual monitor KVM switch (Omniview SOHO).

My mode lines are:-

[Kabuto]

nvidia-glx and nvidia-kernel aren't used for Xorg 7.1. Uninstall both and install just nvidia-drivers. It installs the kernel driver and Nvidia GLX now. Make sure to run eselect opengl set nvidia to switch to NVidia GLX.

[lucida]

http://www.nvnews.net/vbulletin/showthread.php?t=75902

It seems that ReducedBlanking is not a valid option on nvidia driver

btw, I'm using 2407WFP w/7900GT(on DVI) and xorg 7.1, nvidia-drivers 8774 without any problem. The older, "broken" 8756 driver works fine as well.

[ferg]

Ever since I upgraded to Xorg7.1, I've been unable to use the ATI propreitary driver. Whenever I start X, the screen blanks and I have to reboot. However, the R300 driver works fine, if not a lot slower for DRI.

I wonder if this screen blanking could be the cultprit. I'm using a Radeon 9800pro with a Dell 2405FPW.

I'll have a play this weekend.

Cheers
ferg
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[alveraan]

Had exactly the same problem. I'm on amd64, Nvidia Geforce 7900 GT using the nv driver. My monitor is a Samsung Syncmaster 244T. Here is my (working) monitor section:

[ferg]

[joehni]

Same here upgrade to Xorg 7.1 broke my UWXGA resolution (using the nv driver).
Similar hardware as the OP:

[splun549]

Section "Monitor"

Identifier "Massive Dell Megascreen"
HorizSync 31.5 - 82.0
VertRefresh 50-100
Modeline "1920x1200" 154.128 1920 1968 2000 2080 1200 1203 1209 1235 -Hsync -Vsync
Option "DPMS" "True"
Option "ReducedBlanking"
Option "useEDID" "False"
Option "ModeValidation" "NoMaxPClkCheck"
Option "ignoreEDID" "True"
Option "NoDDC"
Option "NoDDC1"
Option "NoDDC2"

EndSection

Thanks a million to the gentoo forums...

[mla]

Can someone PLEASE post a working xorg.conf with the following setup:

xorg 7.1
nvidia proprietary driver
1920x1200 resolution
dvi cable (alt. d-sub)

thanks in advance!

[alveraan]

Here you go:

The bold parts are the relevant parts for graphics, resolution,....
The underlined parts are for composite with beryl, you might not need them.

[mla]

Thank you very much!

Although, i found that applying the following setting in the device section:

Option "ModeValidation" "NoMaxPClkCheck"

made it work. i just told it to use 1920x1200 and did not have to define any special modelines for it! i guess the above setting makes the EDID-modes visible.

thanks again!