Panorama attempts to set write combining caching for the video display memory using MTRRs. This is preferred because using MTRRs affects physical memory. This means that all access to video memory from all drivers and all programs anywhere in the system are affected. If your system does not support this type of MTRR change, Panorama will use PAT to set write combine caching for accesses to video memory that use the Panorama resources. PAT is process specific, however, so it does not affect anything outside of the process that sets it. This means that any other interfaces or programs that do not use Panorama resources will not be affected by Panorama’s setting of PAT and will not have any performance enhancement. DIVE and full screen sessions, for example, do not use Panorama so they will not get any performance improvements if Panorama uses PAT.
32 bit color depths use twice as much memory and system resources including CPU cycles as 16 bit color depths do. Since Panorama is not an accelerated driver, using 16 bit color depths will result in better performance than 32 bit color depths.
How Screen Resolutions work in Panorama
Panorama is a BIOS driven video driver, so the video BIOS in your computer controls almost everything that Panorama can do. When Panorama loads just before the desktop appears, it queries your monitor’s EDID using the DDC and extracts the monitor’s default resolution from that. Then it checks to see if the monitor’s default resolution is already present in the BIOS table of supported resolutions. If not, Panorama attempts to patch the BIOS to add that resolution. This added resolution is known as the Custom Resolution. Then when you open the Screen Object, all the BIOS resolutions, including the custom one will be shown. You can then select whatever resolution you want. Beware that all the BIOS resolutions are shown and some of them may not work for your particular display. This design was deliberately chosen since Panorama cannot determine which resolutions will work and which will not. It was decided that Panorama should display all the BIOS resolutions so that the user can decide which to use. Just because you can select a certain resolution does not mean that it will work.
Note that on many systems, the BIOS also reads the monitor’s EDID on power on and configures itself accordingly. On these type of systems, you must completely power off your system if you change monitors.
The sequence of events when starting a system using Panorama is as follows:
- On power on, the video BIOS attempts to read the monitor’s EDID and sets up BIOS configurations and limitations accordingly. Note that these BIOS imposed configurations and limitations will affect Panorama’s abilities if you change monitors while your system is powered on. Panorama is not loaded or involved during BIOS startup.
- The operating system is booted. Panorama is not loaded or involved during boot.
- PMSHELL is started and this loads Panorama. This occurs at the end of the boot procedure and happens when the screen is cleared right before the screen changes to the Presentation Manager GUI. Note that Panorama is not loaded or running while OS/2 is booting.
- When Panorama starts, it attempts to read the EDID from the monitor. If Panorama cannot read the monitor’s EDID, then steps 5 and 6 are skipped.
- Panorama checks to see if the monitor’s default resolution is already present in the BIOS table of supported resolutions. If not, Panorama attempts to patch the BIOS to add that resolution.
- if “Use Native Resolution” is enabled, Panorama sets the Presentation Manager screen resolution setting to the Monitor’s default resolution. Otherwise the Presentation Manager screen resolution setting is left unchanged.
- Presentation Manager starts and paints the GUI on the screen. Presentation Manager starts at whatever resolution is set in the Presentation Manager settings. This can be changed by using the Screen Object and choosing a resolution of your choice. Note that you should only choose resolutions that are supported by your monitor. The screen object will show all the resolutions that the BIOS can do, but some of them might not work on your monitor.
If you change any of the Panorama settings from the defaults, the operation of Panorama described above no longer takes place and you will only have the default BIOS resolutions available. In this case, any custom resolution must be manually controlled.
Panorama can only patch newer Intel BIOS and ATI/ATOM BIOS. Panorama cannot patch Nvidia and Matrox BIOS. If you have a BIOS that cannot be patched, then you are stuck with whatever resolutions are provided by the BIOS.
Note that the Monitor page of the Screen Object is not part of or related to Panorama in any way. Panorama does not create and does not use any information on the Monitor page of the Screen Object. Any information displayed on the Monitor page may not be accurate and is not useful.
Recovering from Setting a Bad Resolution
- Press CTL-ALT-DEL to start the full screen CAD handler
- Press C to Run Command Shell
- Enter this command:
- Reboot your system.
This will reset your system to 800×600 with 16 bit color. Then you can use the Screen object to select your desired screen settings. Using this command does not change any of the Panorama settings. It just changes the resolution that Presentation Manager uses the same as if you chose 800×600 in the Screen Object.
This section is for version 1.02 and higher. Previous versions had a different command syntax.
WARNING: DO NOT CHANGE CUSTOM RESOLUTION SETTINGS UNLESS YOU FULLY UNDERSTAND WHAT EACH SETTING DOES. The default settings are correct for almost every system. You will not need to change ANY settings except in extremely rare cases. To get back to the default settings, open the Screen object, go to the Custom Resolutions page and click Default.
WARNING: The custom resolution feature cannot be used to configure a resolution higher than the native resolution of the display. Attempting to configure a resolution higher than the native resolution of the display in either the horizontal or vertical direction is not supported.
The custom resolution feature is experimental and may not work in all cases. The custom resolution feature works by patching the video BIOS if necessary. Newer Intel BIOS and ATI/ATOM BIOS are supported. Nvidia and Matrox BIOS are currently not supported. Patching the BIOS does not always work and results may vary. Some BIOS have limitations and won’t work at some resolutions even though the mode table has been patched. There is nothing that can be done in Panorama to fix this limitation in the BIOS.
By default, Panorama will query the display resolution and timing (EDID) via the Display Data Channel (DDC). If this succeeds, Panorama will automatically add the native display resolution to the list of available resolutions that are displayed in the Screen Object settings. You can then select the desired resolution from the list. This is the best method of operation since the exact timings that are provided by the display are used.
If you have previously used a wide screen enabler, then there is a chance that Presentation Manager might use an incorrect resolution when switching to Panorama. To prevent this confusion, switch to a standard SVGA resolution (800×600, 1024×768, or 1280×1024) before installing Panorama. Reboot to make sure that the standard SVGA resolution you have chosen actually works, install Panorama, reboot and select your desired resolution from the list. If you did not do this prior to installing Panorama and the Presentation Manager has selected a non-displayable resolution, you can reset the Presentation Manager selected resolution as described above.
If you have problems with the custom resolution feature, the PanoUtil.exe program can be used to control the custom resolution functions. If you happen to boot to a resolution that cannot be displayed, you can type CTL-ALT-DEL to activate the CAD handler and go to a command prompt to execute these commands. If CTL-ALT-DEL does not work you can boot to the maintenance desktop using ALT-F1 then F4, or boot a different partition. If running the PanoUtil command from a maintenance desktop or from a different partition you must specify the drive to operate on. PanoUtil, like Panorama itself, requires the Presentation Manager so PanoUtil will not run on a system booted to a command line (ALT-F1 then F2 for example).
To reset all the custom resolution settings to the default and set the PM resolution to 800×600:
PanoUtil -r PanoUtil -p PanoUtil -e 0 PanoUtil -d 1
These commands clear any manual resolution, reset the Presentation Manager resolution to 800×600, clears any manual EDID, and enables the Custom Resolution Module, respectively.
To manually set a custom resolution of 1920×1080:
PanoUtil -c 1920 1080
To remove the manual custom resolution:
To completely disable all the custom resolution support:
PanoUtil -d 0
To enable the custom resolution support:
PanoUtil -d 1
To reset the Presentation Manager selected resolution to 800×600:
To see the status of the custom resolution settings:
All of these commands can also be executed from a different boot partition or from the maintenance desktop if you specify the drive to operate on. For example, to change the settings on drive d:, add the drive specification to the end of the desired command:
PanoUtil -s d: PanoUtil -r d: PanoUtil -p d: PanoUtil -c 1920 1080 d: PanoUtil -d 0 d: PanoUtil -d 1 d: PanoUtil -e 0 d:
Collecting a TestLog Log
- If you don’t already have the current version of the TestLog program, you can download it here: Get TestLog
- Make sure your system is booted with Panorama installed
- Open a command prompt.
- Attach the generated LOG file to your ticket.
Systems Running the Debug Kernel Might Get an Unexpected Trace Interrupt
The video BIOS in some systems will sometimes generate an unexpected trace interrupt when the system is running the debug Kernel. You can simply disable the trace interrupt handling using the “vc 1” kernel debugger command. Systems running the retail kernel are not affected.
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