Some questions about eyefinity

[frank]

Seeing it's not possible to get a single monitor rotated using Twinview I'm assuming you went the Xinerama route. Correct?

yes

What I did is switch to the open source Nouveau drivers; these support single monitor rotating just fine (using xrandr) and will support Compiz and the like too.

Thank you, switching to Nouveau was the right advice.
The desktop feels snappy again and apart from missing vsync and minor display (maybe redraw) issues I did not experience stability problems.
kernel 2.6.37, gnome 2.32, no compiz (yet)

btw:
First I tried to adapt my xorg.conf but accidentially started without any xorg.conf into gnome 2.x and was impressed by how easy it was to set up, arrange and rotate the displays.

Frank

[BlackStar]

Does nVidia not have this problem? I thought it was an X issue that wasn't brand related.

Thanks for your input, nice to hear from people who have experience with both ATI and nVidia.

It does, when you use TwinView. It doesn't, when you use Xinerama (which I used here). Unfortunately, Xinerama sucks so it's not a solution.

Yeah, it's an X issue, should have been filed under "Negative (both)".

[Sylarr]

Negative (Ati):
- the desktop expands to a single huge rectangle, meaning the mouse can move outside the visible area. This is a known X server issue and is expected to be fixed in an upcoming release.

Does nVidia not have this problem? I thought it was an X issue that wasn't brand related.

Thanks for your input, nice to hear from people who have experience with both ATI and nVidia.

[BlackStar]

I moved my dual monitor setup from a Nvidia 9500GT to an Ati 4850. Both monitors are 1920x1080, first monitor is rotated into portrait mode. Impressions:

Positive (Ati):
- acceleration (2d and 3d) works correctly
- compiz works
- video works
- audio works
- setup was trivial through amdcccle (catalyst) or the relevant ubuntu utility (radeon).
- excellent support for custom video modes (catalyst), including 24p (which is great for video).

Negative (Ati):
- vsync doesn't work with fglrx at all. This is a known Ati issue, and is expected to be fixed in the 11.1 drivers.
- vsync doesn't work on rotated monitors with radeon. This is a known driver issue.
- the desktop expands to a single huge rectangle, meaning the mouse can move outside the visible area. This is a known X server issue and is expected to be fixed in an upcoming release.

Positive (nvidia):
- Xv uses PC color range (0-255) rather than TV range (15-229).

Negative (nvidia):
- rotation requires Xinerama, which disables hardware and video acceleration.
- vsync doesn't work on rotated monitors at all. This is a known driver issue.
- the open source drivers (nouveau) would become unstable with rotated monitors.

Negative (both):
- one monitor will always have incorrect subpixel antialiasing. This is a fontconfig/freetype/xft/whatever issue, because they fail to switch subpixel direction in accord to monitor rotation.

All in all, I'm pretty happy with this setup. Ati works better than Nvidia here, as Nvidia requires Xinerama which sucks.

[Sylarr]

Nvidia can, my setup is 2560x1440 landscape plus 1200x1600 portrait on a 8800 GT.

I'm running a setup very similar to yours: I have a rotated 20" 1200x1600 monitor on the left and a non-rotated 30" 2560x1600 to the right.

Works fine BUT:

This setup is dog slow (compared to NOT running a monitor in portrait mode or Windows 7). It seems like rendering on the 90? rotated screen is completely un-accelerated.

Seeing it's not possible to get a single monitor rotated using Twinview I'm assuming you went the Xinerama route. Correct? The performance of Xinerama is as you point out terrible and it wasn't acceptable for me. What I did is switch to the open source Nouveau drivers; these support single monitor rotating just fine (using xrandr) and will support Compiz and the like too. Even most games should work (see: http://www.phoronix.com/scan.php?pag...a_nouveau_q111).

I am already hit by slow 2D desktop performance, not even considering 3D.
For 2D one screen takes 4 bytes (RGBA) * (2560 + 1200) * 1600 = 24 MB.
A 8800 GT with 512 MB RAM should be just fine to handle this and still have room for back buffers etc.

FWIW, I'm using this setup with a 7600GS which has 256MB and it works fine. (Kernel 2.6.36, Mesa 7.9, libdrm 2.4.22).

With multiple monitors, the width of the desktop is the sum of the widths of the various monitor resolutions while the height is the largest height among your various monitors resolution.

This is a bit nitpicking but the above is not correct if you have one monitor placed higher than the other (e.g. above each other). A better way of putting it: "the largest square that will fit all your monitors".

In most cases, rotating one monitor to portrait causes the desktop size to increase.
This increase in desktop size is what leads to the slow down that you experienced.

This is not what's causing the decrease in performance in this case. The problem is the closed source nVidia drivers do not support rotating a single monitor and therefore if you still want to you have to resort to Xinerama, which is really slow.

@frank, if you need any help getting this setup using Nouveau I'd be happy to assist.

[Pfanne]

concerning wine and multimonitor setups.
is there ANY way to efficiently lock the mouse cursor into the application window?
games like warcraft 3 are especially problematic since its almost impossible to scroll on the borders of the window.
i wrote a really hackish workarround for this, that resets the cursor into the window every few milliseconds but its not really satisfying.
(sorry for hijacking this thread)

[frank]

With multiple monitors, the width of the desktop is the sum of the widths of the various monitor resolutions while the height is the largest height among your various monitors resolution.

sure

In most cases, rotating one monitor to portrait causes the desktop size to increase.
This increase in desktop size is what leads to the slow down that you experienced.

No. Handling 50% more pixels can not reasonably cause a slowdown of factor 10 or so.

With the setup you are planning on getting I would recommend a card with 2Gb.

I am already hit by slow 2D desktop performance, not even considering 3D.
For 2D one screen takes 4 bytes (RGBA) * (2560 + 1200) * 1600 = 24 MB.
A 8800 GT with 512 MB RAM should be just fine to handle this and still have room for back buffers etc. Under Windows 7 or Linux with UNROTATED displays, it definitely is.

That's why I asked in the AMD section of the forum: does a setup like mine work good in 2D (3D/compiz would be nice to have) on AMD? As I may add my 3rd TFT to this display group AMD is also my first option compared to adding a 2nd NVidia card.

Frank

[pwyll]

Nvidia can, my setup is 2560x1440 landscape plus 1200x1600 portrait on a 8800 GT.
Works fine BUT:

This setup is dog slow (compared to NOT running a monitor in portrait mode or Windows 7). It seems like rendering on the 90? rotated screen is completely un-accelerated.

Will this setup work better using a 5770 or 6850?
Which driver do I need ? Proprietary, open source or open source WIP (git)?
(a third monitor, 1920x1200 landscape, will be connected also)

Is there any way that compiz/KDE4 is supported?

Frank

With multiple monitors, the width of the desktop is the sum of the widths of the various monitor resolutions while the height is the largest height among your various monitors resolution.

In most cases, rotating one monitor to portrait causes the desktop size to increase.
This increase in desktop size is what leads to the slow down that you experienced.

With multiple monitors and the larger desktop sizes they have you will get better performance with cards that have larger RAM. With the setup you are planning on getting I would recommend a card with 2Gb.

I'd go with the 6850 rather than the 5770. Or even better still get a 6950 2GB if its within your budget.

For best performance with any recent ATI card the proprietary driver is what you want.

My setup is two 1440x900 and one 1920x1080 in portrait mode running on a 6970 (this was originally a 6950 that I upgraded via a bios mod). KDE 4.5 works fine.

Hope this helps.

[frank]

eyefinity does what you want.

In fact, it is superior to TwinView in most ways:
- it supports xrandr and randr 1.3.
- it reports correct refresh rates (Nvidia reports random rates)
- it allows you to rotate one or more monitors into portrait mode, keeping the rest in landscape. Nvidia simply cannot do this.

Nvidia can, my setup is 2560x1440 landscape plus 1200x1600 portrait on a 8800 GT.
Works fine BUT:

This setup is dog slow (compared to NOT running a monitor in portrait mode or Windows 7). It seems like rendering on the 90? rotated screen is completely un-accelerated.

Will this setup work better using a 5770 or 6850?
Which driver do I need ? Proprietary, open source or open source WIP (git)?
(a third monitor, 1920x1200 landscape, will be connected also)

Is there any way that compiz/KDE4 is supported?

Frank

[rohcQaH]

Oh, one more thing: windows games and/or wine are usually unaware of multiscreen setups - they use an ancient X extension for commands like "set resolution to x*y", which doesn't translate to multiple monitors at all.
It worked with nvidia because TwinView basically fakes a multiscreen setup as a single screen resolution.

With xrandr, you'll need some workarounds - worst case, an init script that sets up xrandr as desired, then launches the game in windowed mode with a huge, borderless window. Sometimes it's enough to set the correct resolution to some .ini - the modesetting call will fail (there's no fitting single screen resolution) but the game will continue anyway.