VMD-L Mailing List

From: John Stone (johns_at_ks.uiuc.edu)
Date: Wed Feb 11 2004 - 20:02:26 CST

Just to provide more followup info on this:
  VMD has no inherent limits on the maximum size of the OpenGL
graphics window. If your graphics card had a 65,000x65,000
resolution display, VMD would work just fine on it. The problem
is that some of the Linux video drivers incorrectly enable features
such as multisample antialiasing, stencil buffers, and stereo in
display modes that are beyond the video memory available on the board.
In the NVidia cards instead of crashing, their cards start paging video
memory and the performance suffers drastically, ATIs driver apparently
isn't handling this situation well at all. In truth, if the video card
doesn't have enough memory to enable these features, it should be
telling VMD 'no' when VMD asks for an OpenGL context with all of those
features enabled. If they answer 'yes', then VMD should be able to
resize the OpenGL window to the size of the entire screen and not
encounter problems. The slow rendering and/or crashing people have
observed with large window sizes are a direct result of the current
implementation of these ATI and NVidia OpenGL drivers. I'd strongly
recommend that people report these problems to ATI and NVidia when
they occur so that these bugs are fixed in future versions of their
video drivers. Most companies have a very limited number of driver
engineers, so they tend to follow the "squeaky wheel gets the grease"
prioritization when fixing bugs.

  John

On Thu, Feb 12, 2004 at 10:14:28AM +1100, Dallas Warren wrote:
> Chris,
>
> I am running:
> VMD 1.8.2,
> RHEL AS 2.1
> ATI FireGL X1-256 with fglrx-glc22-4.3.0-3.2.8
> XFree86-4.3.0-3.2.8
>
> >Using the Linux binary VMD (vmd-1.8.2) crashes when maximized (or
> sometimes resized) with
> >Has anyone else run into this?
>
> I have observed this as well. There appears to be an upper size limit to
> the VMD window that the graphics card/driver can handle. And even resizing
> the window can crash VMD.
>
> >Is there a maximum resolution (for VMD)? i.e. would 1600x1200 cause
> >problems?
>
> I haven't checked to see exactly when the problem kicks in, but I use a
> 1100x1100 window for VMD without any issues.
>
> The appropriate section of my XF86Config file is attached, FYI.
>
> Catch ya,
>
> Dr. Dallas Warren
> Research Fellow
> Department of Pharmaceutical Biology and Pharmacology
> Victorian College of Pharmacy, Monash University
> 381 Royal Parade, Parkville VIC 3010
> dallas.warren_at_vcp.monash.edu.au
> +61 3 9903 9083
> --------------------------------------------------------------------------
> When the only tool you own is a hammer, every problem begins to resemble a
> nail.

> Section "Device"
>
> # === disable PnP Monitor ===
> #Option "NoDDC"
> # === disable/enable XAA/DRI ===
> # === Screen Management ===
> # Note: When OpenGL Overlay is enabled, Video Overlay
> # will be disabled automatically
> # vendor=1002, device=4e47
> Identifier "ATI Graphics Adapter"
> Driver "fglrx"
> BoardName "FireGL X1 256"
> Option "no_accel" "no"
> Option "no_dri" "no"
> Option "DesktopSetup" "0x00000000"
> Option "MonitorLayout" "AUTO, AUTO"
> Option "IgnoreEDID" "off"
> Option "HSync2" "unspecified"
> Option "VRefresh2" "unspecified"
> Option "ScreenOverlap" "0"
> Option "NoTV" "yes"
> Option "TVStandard" "NTSC-M"
> Option "TVHSizeAdj" "0"
> Option "TVVSizeAdj" "0"
> Option "TVHPosAdj" "0"
> Option "TVVPosAdj" "0"
> Option "TVHStartAdj" "0"
> Option "TVColorAdj" "0"
> Option "GammaCorrectionI" "0x00000000"
> Option "GammaCorrectionII" "0x00000000"
> Option "Capabilities" "0x00000000"
> Option "VideoOverlay" "on"
> Option "OpenGLOverlay" "off"
> Option "CenterMode" "off"
> Option "PseudoColorVisuals" "off"
> Option "Stereo" "off"
> Option "StereoSyncEnable" "1"
> Option "FSAAScale" "1"
> Option "FSAADisableGamma" "yes"
> Option "FSAACustomizeMSPos" "no"
> Option "FSAAMSPosX0" "0.000000"
> Option "FSAAMSPosY0" "0.000000"
> Option "FSAAMSPosX1" "0.000000"
> Option "FSAAMSPosY1" "0.000000"
> Option "FSAAMSPosX2" "0.000000"
> Option "FSAAMSPosY2" "0.000000"
> Option "FSAAMSPosX3" "0.000000"
> Option "FSAAMSPosY3" "0.000000"
> Option "FSAAMSPosX4" "0.000000"
> Option "FSAAMSPosY4" "0.000000"
> Option "FSAAMSPosX5" "0.000000"
> Option "FSAAMSPosY5" "0.000000"
> Option "UseFastTLS" "0"
> Option "BlockSignalsOnLock" "on"
> Option "UseInternalAGPGART" "yes"
> Option "ForceGenericCPU" "no"
> BusID "PCI:1:0:0"
> EndSection
>
> Section "Screen"
> #Option "backingstore"
> Identifier "Screen0"
> Device "ATI Graphics Adapter"
> Monitor "Monitor0"
> DefaultDepth 24
> SubSection "Display"
> # initial origin if mode is smaller than desktop
> # "2048x1536"
> Virtual 1600 1200
> Depth 24
> Modes "1920x1440" "1792x1344" "1600x1200" "1400x1050" "1280x1024" "1280x960" "1152x864" "1024x768" "800x600" "640x480"
> EndSubSection
> EndSection 

-- 
NIH Resource for Macromolecular Modeling and Bioinformatics
Beckman Institute for Advanced Science and Technology
University of Illinois, 405 N. Mathews Ave, Urbana, IL 61801
Email: johns_at_ks.uiuc.edu                 Phone: 217-244-3349              
  WWW: http://www.ks.uiuc.edu/~johns/      Fax: 217-244-6078