VDP_SetMode should not touch the frequency setting

[Jeroen-Smael]

When I do VDP_SetMode(VDP_MODE_SCREEN5); the VDP frequency is set to 50Hz, even if it was set to 60Hz before. This is undesirable behavior. The VDP frequency should not be touched.

Reproduction scenario: Program snippet:

#include "msxgl.h"
#include "vdp.h"

void main()
{
    VDP_SetMode(VDP_MODE_SCREEN5);
    while (true) {
        // no need to do anything
    }
}

Start with e.g. CBIOS MSX2+ (which runs at 60Hz normally)

After the screen has been set, you can see in the openMSX / menu / advanced / toys and utilities / info panel that the frequency has been changed to 50Hz.

[aoineko-fr]

To prevent 50 Hz to be set by VDP_SetMode() on MSX2 you can either, in your msxgl_config.h:

• Set VDP_USE_DEFAULT_SETTINGS to 0 (you will have to handle manually the reset of VDP registers)
• Set VDP_INIT_50HZ to VDP_INIT_DEFAULT (keep previous frequency setting)