DynamicTwinView and randr

arundel · 10-19-09, 05:48 PM

hi there,

with DynamicTwinView set to false in xorg.conf i'm getting the following xrandr results:

Code:

Screen 0: minimum 320 x 175, current 1680 x 1050, maximum 1680 x 1050
default connected 1680x1050+0+0 (normal left inverted right) 0mm x 0mm
   1680x1050      60.0*
   1152x864       75.0
   1024x768       85.0     75.0     70.0     60.0     87.0
   800x600        85.0     75.0     72.0     60.0     56.0     70.0     65.0
   640x480        85.0     75.0     73.0     60.0
   400x300        85.0     75.0     72.0     60.0     56.0
   1400x1050      75.0     60.0
   1280x1024      85.0     75.0     60.0
   1280x960       85.0     60.0
   960x720        75.0     60.0
   928x696        75.0     60.0
   896x672        75.0     60.0
   832x624        75.0
   720x400        85.0
   700x525        75.0     60.0
   640x512        85.0     75.0     60.0
   640x400        85.0
   640x350        85.0
   576x432        75.0
   512x384        85.0     75.0     70.0     60.0     87.0
   416x312        75.0
   360x200        85.0
   320x240        85.0     75.0     73.0     60.0
   320x200        85.0
   320x175        85.0

if DynamicTwinView is set to true (default) i'm getting:

Code:

Screen 0: minimum 320 x 175, current 1680 x 1050, maximum 1680 x 1050
default connected 1680x1050+0+0 (normal left inverted right) 0mm x 0mm
   1680x1050      50.0*
   1152x864       51.0
   1024x768       52.0     79.0     80.0     81.0     82.0     83.0
   800x600        53.0     87.0     88.0     89.0     90.0     91.0     92.0     93.0     94.0     95.0
   640x480        54.0     99.0    100.0    101.0    102.0    103.0    104.0
   400x300        55.0    109.0    110.0    111.0    112.0
   1400x1050      56.0     75.0
   1280x1024      57.0     76.0     77.0
   1280x960       58.0     78.0
   960x720        59.0     84.0
   928x696        60.0     85.0
   896x672        61.0     86.0
   832x624        62.0
   720x400        63.0
   700x525        64.0     96.0
   640x512        65.0     97.0     98.0
   640x400        66.0
   640x350        67.0
   576x432        68.0
   512x384        69.0    105.0    106.0    107.0    108.0
   416x312        70.0
   360x200        71.0
   320x240        72.0    113.0    114.0    115.0
   320x200        73.0
   320x175        74.0

is this to be expected? i'm running NVIDIA-FreeBSD-x86-190.40 on 9-CURRENT.

cheers.
alex

**zander** · 10-19-09, 06:08 PM

Yes, see e.g. http://us.download.nvidia.com/freebs...hapter-07.html:

Why is the refresh rate not reported correctly by utilities that use the XRandR X extension (e.g., the GNOME "Screen Resolution Preferences" panel, `xrandr -q`, etc)?

The XRandR X extension is not presently aware of multiple display devices on a single X screen; it only sees the MetaMode bounding box, which may contain one or more actual modes. This means that if multiple MetaModes have the same bounding box, XRandR will not be able to distinguish between them.

In order to support DynamicTwinView, the NVIDIA X driver must make each MetaMode appear to be unique to XRandR. Presently, the NVIDIA X driver accomplishes this by using the refresh rate as a unique identifier.

You can use `nvidia-settings -q RefreshRate` to query the actual refresh rate on each display device.

This behavior can be disabled by setting the X configuration option "DynamicTwinView" to FALSE.

For details, see Chapter 12, Configuring TwinView.

arundel · 10-20-09, 11:19 AM

thanks a lot for the hint. now i've set DynamicTwinView to false. however `nvidia-settings -q RefreshRate` says:

Code:

  Attribute 'RefreshRate' (otaku:0.0; display device: DFP-0): 59,95 Hz.
    'RefreshRate' is an integer attribute.
    'RefreshRate' is a read-only attribute.
    'RefreshRate' is display device specific.
    'RefreshRate' can use the following target types: X Screen, GPU.

and `xrandr -q` says:

Code:

Screen 0: minimum 320 x 175, current 1680 x 1050, maximum 1680 x 1050
default connected 1680x1050+0+0 (normal left inverted right) 0mm x 0mm
   1680x1050      75.0*    60.0  
   1400x1050      75.0     60.0  
   1280x1024      85.0     75.0     60.0  
   1280x960       85.0     60.0  
   1152x864       75.0  
   1024x768       85.0     75.0     70.0     60.0     87.0  
   960x720        85.0     75.0     60.0  
   928x696        75.0     60.0  
   896x672        75.0     60.0  
   832x624        75.0  
   800x600        85.0     75.0     72.0     60.0     56.0     70.0     65.0  
   720x400        85.0  
   700x525        75.0     60.0  
   640x512        85.0     75.0     60.0  
   640x480        85.0     75.0     73.0     60.0  
   640x400        85.0  
   640x350        85.0  
   576x432        75.0  
   512x384        85.0     75.0     70.0     60.0     87.0  
   416x312        75.0  
   400x300        85.0     75.0     72.0     60.0     56.0  
   360x200        85.0  
   320x240        85.0     75.0     73.0     60.0  
   320x200        85.0  
   320x175        85.0

so...is my display running at 75 mhz or 59,95 mhz?
alex

**zander** · 10-24-09, 03:10 PM

it's running at 59,95Hz. XRandR reports the front-end timings, nvidia-settings the back-end timings. It seems both 60Hz and 75Hz were validated as back-end timings, but e.g. the Force Full GPU Scaling setting forced the driver to use the display's native timings.

10-19-09, 06:08 PM	#2
zander NVIDIA Corporation Join Date: Aug 2002 Posts: 3,740	Re: DynamicTwinView and randr Yes, see e.g. http://us.download.nvidia.com/freebs...hapter-07.html: Why is the refresh rate not reported correctly by utilities that use the XRandR X extension (e.g., the GNOME "Screen Resolution Preferences" panel, `xrandr -q`, etc)? The XRandR X extension is not presently aware of multiple display devices on a single X screen; it only sees the MetaMode bounding box, which may contain one or more actual modes. This means that if multiple MetaModes have the same bounding box, XRandR will not be able to distinguish between them. In order to support DynamicTwinView, the NVIDIA X driver must make each MetaMode appear to be unique to XRandR. Presently, the NVIDIA X driver accomplishes this by using the refresh rate as a unique identifier. You can use `nvidia-settings -q RefreshRate` to query the actual refresh rate on each display device. This behavior can be disabled by setting the X configuration option "DynamicTwinView" to FALSE. For details, see Chapter 12, Configuring TwinView.

10-24-09, 03:10 PM	#4
zander NVIDIA Corporation Join Date: Aug 2002 Posts: 3,740	Re: DynamicTwinView and randr it's running at 59,95Hz. XRandR reports the front-end timings, nvidia-settings the back-end timings. It seems both 60Hz and 75Hz were validated as back-end timings, but e.g. the Force Full GPU Scaling setting forced the driver to use the display's native timings.