DPMS screen blanking

[mark_k]

VESA DPMS screen blanking allows the computer to tell the monitor to go into a lower-power state by disabling one or both video sync signals.

Some Amiga programs (well, Debian Linux is probably the only Amiga program) can disable the horizontal and/or vertical sync signals. Debian does that by setting HSSTRT and HSSTOP (in the case of disabling horizontal sync) to the same value which is outside the displayed range.

WinUAE seems to handle that okay. When I tested it the Amiga screen shows as all black when blanked. Or maybe Debian sets the screen to all black before turning off the sync(s), and WinUAE continues to display the Amiga image?

It would be good if there could be some indication in the status bar when H/V syncs are disabled, so the user can tell whether there is just a blank screen on the Amiga side, or the DPMS screen blanker has activated. You could also stop rendering into the emulation window when one of the syncs is disabled which could reduce CPU use slightly I guess.

[Toni Wilen]

WinUAE will still display the image, at least it attempts but I guess nothing would be shown (even if display wasn't blanked first) due to weird sync positions.

Not worth the trouble unless there is AmigaOS compatible version of blanking program

[mark_k]

To get DPMS blanking to work in AmigaOS I think you'd need the monitor driver to support it (poking custom registers from a user program is probably not a good idea...).

If you want to experiment, you can boot the Aminet Debian HDF. Log in as root, then quit X by typing /etc/init.d/xdm stop
Log in as root then run this command: setterm -blank 1 -powersave hsync -powerdown 2

After a minute of inactivity horizontal sync signals are disabled. WinUAE log says:

PAL mode dblscan V=55.3710Hz H=31113.1140Hz (114x561+1) IDX=10 (PAL) D=1 RTG=0
P96FREQ: 561*55.3710 = 31063.1579 / 55.4 = 561
BEAMCON0=5BB6 VTOTAL=0230  HTOTAL=0071
  HSSTOP=0074 HBSTRT=0001  HBSTOP=0023
  VSSTOP=000E VBSTRT=0230  VBSTOP=0030
  HSSTRT=0074 VSSTRT=000C HCENTER=0045
PAL mode dblscan V=55.3710Hz H=31113.1140Hz (114x561+1) IDX=10 (PAL) D=1 RTG=0
P96FREQ: 561*55.3710 = 31063.1579 / 55.4 = 561

After another couple of minutes:

BEAMCON0=5BB6 VTOTAL=0230  HTOTAL=0071
  HSSTOP=0074 HBSTRT=0001  HBSTOP=0023
  VSSTOP=000E VBSTRT=0230  VBSTOP=0030
  HSSTRT=0074 VSSTRT=0233 HCENTER=0045
BEAMCON0=5BB6 VTOTAL=0230  HTOTAL=0071
  HSSTOP=0074 HBSTRT=0001  HBSTOP=0023
  VSSTOP=0233 VBSTRT=0230  VBSTOP=0030
  HSSTRT=0074 VSSTRT=0233 HCENTER=0045
BEAMCON0=5BB6 VTOTAL=0230  HTOTAL=0071
  HSSTOP=0074 HBSTRT=0001  HBSTOP=0023
  VSSTOP=0233 VBSTRT=0230  VBSTOP=0030
  HSSTRT=0074 VSSTRT=0233 HCENTER=0045
Buffer size (656*1) Native
D3D9Ex: working texture allocated pre 656*1, post 768*576, bits per pixel 16
D3D9Ex: 656*1 texture allocated, bits per pixel 16
PAL mode dblscan V=55.3710Hz H=31113.1140Hz (114x561+1) IDX=10 (PAL) D=1 RTG=0
P96FREQ: 561*55.3710 = 31063.1579 / 55.4 = 561
POS (0 0 768 576) - (-56 -287 712 289)[768,576] (0 0)
BEAMCON0=5BB6 VTOTAL=0230  HTOTAL=0071
  HSSTOP=0074 HBSTRT=0001  HBSTOP=0023
  VSSTOP=0233 VBSTRT=0230  VBSTOP=0030
  HSSTRT=0074 VSSTRT=0233 HCENTER=0045
PAL mode dblscan V=55.3710Hz H=31113.1140Hz (114x561+1) IDX=10 (PAL) D=1 RTG=0
P96FREQ: 561*55.3710 = 31063.1579 / 55.4 = 561