Reply 20 of 66, by Start me up
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- Newbie
The graphics driver became a bit more mature since my last life sign in here. Here is the summary:
5.00.2196.0022
- Bug fix: The mysterious blue screen bug was fixed. Switching from one Gen7LC-display mode directly to another Gen7LC-display mode is now possible.
5.00.2196.0023
- Bug fix: Some invalid clock generator speeds were available.
5.00.2196.0024
- Bug fix: A validity check was incorrect implemented which allowed using too big image buffers.
- Bug fix: The compatibility with some screens was improved (which caused a black screen instead of seeing the payload)
- Bug fix: The graphics circuit "ValleyView" has serious problems with VGA. The support for VGA is now deactivated when handling this graphics circuit. Maybe a better work-around comes somewhen in the future.
- New: the driver now offers Gen7LC-display modes defined by the driver author.
The list of display modes defined by the driver author is generated by iterating over all possible combinations of color resolutions, image refreshing rates, x-resolutions and y-resolutions. The driver iterates over
- 3 color resolutions: 256 colors, 16 bits and 32 bits
- 13 image refreshing rates: 25, 30, 50, 56, 60, 70, 72, 75, 85, 100, 120, 144 and 240 images per second
- 16 x-resolutions: 320; 360; 640; 720; 768; 800; 960; 1,024; 1,280; 1,440; 1,600; 1,920; 2,048; 2,560; 3,200 and 3,840 pixels
- 21 y-resolutions: 200; 240; 350; 400; 480; 576; 600; 768; 900; 960; 1,024; 1,050; 1,080; 1,152; 1,200; 1.440; 1,536; 2,048; 2,160; 2,400 and 3,072 lines
The driver has some limitations at the moment. This is why only about 10,000 of these ~13,000 display modes are valid and exposed to the operating system.
However, this approach already shows one big benefit of the direct communication compared to using the VESA BIOS Extension (VBE) where one can easily be stuck with 5 to 15 display modes.
The driver needs about 290 machine cycles per valid list entry (including the time to read the registry for concealed display modes, which is quite a percentage of these cycles) to generate/write this list. However, the display program of the control panel needs about 190,000 machine cycles per list entry to read the list. When the display program opens (right click on the desktop and then select "properties"), then the programm asks the driver for the list not just once but 4 times. So there is a delay of about 5 seconds to open the program. If this is too long, then the registry can be used to conceal unneeded display modes (see the help file). Fortunately, this "5 seconds"-delay is only in the display program of the control panel and not in the boot time nor when setting up a display mode.
These new versions are a step forward in maturing the Gen7LC support. But there are still some bugs left and some limitations to be lifted.