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Old 01-25-10, 07:07 AM   #1
te36
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Default Scaling for DFP, how to control/modify...

NVidia G210 under 190.42 driver and Xorg 7.3 connecting via HDMI to a 720p projector (PT-AX100E). Projector provides a bunch of resolutions via EDID, and 1920x1080@60Hz/i is the first resolution and the projector also claims that it is supported (see appended Xorg.0.log).

The interesting thing is that whatever resolution i am selecting via xrandr, i think the nvidia driver is upscaling it to 1920x1080@60Hz/i - because the projector does show in the OSD that as the resolution (instead of let's say 720p that's selected via xrandr). There are also some indications in Xorg.0.log that make me think this is the right interpretation:

BestFit Scaled and BestFit AspectScaled are identical;
(II) Jan 23 11:10:30 NVIDIA(GPU-0): collapsing BestFit AspectScaled.
(II) Jan 23 11:10:30 NVIDIA(GPU-0): BestFit Centered and BestFit Scaled are identical;
(II) Jan 23 11:10:30 NVIDIA(GPU-0): collapsing BestFit Scaled.

Q1: Is this the correct interpretation ?

Q2: Is this pretty much what i should expect to be the function of

Option "FlatPanelProperties" "Scaling = Scaled" (or centered).

Now, here is where it is getting interesting: I do like the idea that the Nvidia driver is scaling the video, but i would like to enforce that for a new resolution that i do want to define via a modeline. Aka: i am looking for a way to define a modeline with a particular resolution/refresh-rate and then also say that it should be scaled to a particular resolution on the actual HDMI signal. Is this possible somehow ?

If not in a modeline, how about xrandr: There is also in xrandr 1.3 a scale/transform option - unfortunately i could never make it do anything more than give me "Segmentation Fault", and i did not find any good example on how to use it, and the manual is not very instructive.

What i want to do is this: The projector being natively 720p is of course quite stupid in announcing EDID that will cause 1080i60 resolution to be the default resolution, because that will make the NVidia-driver scale up the video, and the projector scales it down to the panel resolution of 720p again. Looks astoundinglly good, but it is not pixel exact, so there is some error that i would not know how to crrect in up/downscaling - so not ideal for photo display or desktop surface. So in general i would want to disable this scaling and use native 720p resolution of the projector.

But: The projector does not synchronize to any 720p24, but it does have 1080p24 that it synchronizes to. So now i would like to set up a 720p24 resolution which the Nvidia driver should upscale to the 1080p24 resolution - such that i have jitter free 24p display. This is because xbmc would only be able to select between 720p50, 720p60 or 720p24 automatically, but not between 720p50, 720p60 or 1080p24.

Actually, i got also an even older projector (VPL-VW10HT) where the NVidia windows XP driver does nicely scale a 1280x720 framebuffer over component output up to a 1920x1080i signal, and the projector then downscales it to it's native 1366x768 with overscan, and this whole up and downscale actually manages to provide a fairly moiree free 1:1 mapped 720p desktop (which i natively could not achieve because the projector always does do overscan).

Now i want to actually change that machine to Linux, but i have no clue how i could force the Nvidia Linux driver to do the same upscaling for me - over component output, not DFP (no HDMI/DVI on that old projector).

Thanks
Attached Files
File Type: log Xorg.0.log (70.2 KB, 107 views)
File Type: txt xorg.conf.txt (1.7 KB, 148 views)
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Old 01-25-10, 08:43 AM   #2
jpterj
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Default Re: Scaling for DFP, how to control/modify...

Option "FlatPanelProperties" "Scaling = Native" should make it possible to select whatever resolution the EDID reports as supported.
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Old 01-25-10, 01:10 PM   #3
te36
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Default Re: Scaling for DFP, how to control/modify...

Right, but how do i then add scaling in the nvidia driver for a new modeline i want to define..
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Old 01-26-10, 06:14 AM   #4
jpterj
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Default Re: Scaling for DFP, how to control/modify...

Quote:
Originally Posted by te36 View Post
Right, but how do i then add scaling in the nvidia driver for a new modeline i want to define..
First of all I don't think you should usually need to define any modelines any more. If you look into the Xorg.0.log you will see the validated modes:
Code:
(II) Jan 23 11:10:30 NVIDIA(0): --- Modes in ModePool for Panasonic AX-100 (DFP-0) ---
(II) Jan 23 11:10:30 NVIDIA(0): "nvidia-auto-select" : 1280 x  720 @  60.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "1280x720"           : 1280 x  720 @  60.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "1280x720_60"        : 1280 x  720 @  60.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "1280x720_60_0"      : 1280 x  720 @ 59.94/60 Hz (CEA-861B Format 4) (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "1280x720_50"        : 1280 x  720 @  50.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "720x576"            :  720 x  576 @  50.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "720x576_50"         :  720 x  576 @  50.0 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "720x480"            :  720 x  480 @  59.9 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "720x480_60"         :  720 x  480 @  59.9 Hz  (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "640x480"            :  640 x  480 @ 59.94/60 Hz Interlace (CEA-861B Format 1) (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): "640x480_60"         :  640 x  480 @ 59.94/60 Hz Interlace (CEA-861B Format 1) (from: EDID)
(II) Jan 23 11:10:30 NVIDIA(0): --- End of ModePool for Panasonic AX-100 (DFP-0): ---
(II) Jan 23 11:10:30 NVIDIA(0): 
(II) Jan 23 11:10:30 NVIDIA(0): Assigned Display Device: DFP-0
(==) Jan 23 11:10:30 NVIDIA(0): 
(==) Jan 23 11:10:30 NVIDIA(0): No modes were requested; the default mode "nvidia-auto-select"
(==) Jan 23 11:10:30 NVIDIA(0):     will be used as the requested mode.
These can be accessed directly in your xorg.conf as e.g. "1280x720_50"

But why not use nvidia-settings to do this instead of editing the xorg.conf file?

I used to have to edit the xorg.conf file to get things as I wanted, but with the later drivers I find it easier to use nvidia-settings. I usually just set scaling to native, select a specific refresh rate instead of Auto and can then just select the resolution. Then just save to xorg.conf.
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Old 01-28-10, 06:56 AM   #5
te36
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Default Re: Scaling for DFP, how to control/modify...

Well, nvidia-settings is a nice frontend, but it does also only change the xorg.conf file. I am not aware of any xorg.conf syntax that would allow me to do what the Xorg server does when it uses non-native scaling, aka: instruct the xorg server to scale. That's why i am asking if it is possible at all, via xorg.conf or via xrandr 1.3.
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Old 01-28-10, 08:11 AM   #6
P.Kosunen
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Default Re: Scaling for DFP, how to control/modify...

Code:
Option "FlatPanelProperties" "Scaling = Native"
Option "metamodes" "1280x720_60 +0+0; 1280x720_50 +0+0; 1920x1080_24 +0+0"
You can set (EDID) refresh rate/resolution with metamodes.

Edit: ... Should read the question first.
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