GroovyArcade LiveCD and intel chipset

[kokoko3k]

Hi,
I just tried to connect a little atom netbook to the cab and booting it with the latest stable groovyarcade live-usb.
The netbook has an old gma945, and i'm unable to get any output to the crt, which stays black.
The system works fine with a desktop pc installed with a pre-kms system and a radeon 9xxx gpu.
Is the gma945 supposed to support 15khz modes?

Thanks for reading.

[Calamity]

You have two issues there, the first one is GA won't output through a laptop's vga, it needs to use the primary output which in a laptop is always the internal LCD, the second problem is Intel gpus do not support custom video in the way we need it (even KMS drivers).

[kokoko3k]

Thanks for answering.

I understand that the first problem (the dual display) could appear as an issue, but in the end if one needs to watch the boot process status, he can just look at the netbook screen, what is really important is the xorg output, right?

So, playing with a "real" arch installation, i managed to output some modelines to the crt generated by switchres.
Basically, it seems to work with higher horizontal resolutions.
Eg: 640x280 wont work, but 1280x280 does.
Interlaced modes works too.
It seems to me that if pixelclock is in range 19-21 (i'm not 100% sure it is accurate), then the mode will work.
Can this info be used by GroovyArcade to work on intel gma?
Is there a way to tell switchres to use that pixelclock range?
With my noobish notions i wasn't able to do that using the -crt_range parameters, but i'm pretty sure it could be done.
I'm reading about a dotclock_min used to work in switchres years ago, but it seems switchres won't accept it anymore.
Some suggestions in that regard?

thanks!

-edit-
in the switchres source, there are some references to dotclock min and max, but unfortunately they don't seem to be used:

Code: [Select]

# in SwitchResLinux-1.443-ced8096/extra/switchres.conf:
# These currently are not even used
# DotClock limits of video card
#DotClockMin=1000000
#DotClockMax=90000000
#


Code: [Select]

grep -ri dotclockmin *
SwitchResLinux-1.443-ced8096/extra/switchres.conf:#DotClockMin=1000000
SwitchResLinux-1.443-ced8096/switchres.h:       int    dotclockmin;
SwitchResLinux-1.52/switchres.h:        int    dotclockmin;



[Calamity]

Can you confirm that 1280x280 is actually 15-16 kHz, or rather a double-scanned or scaled resolution?
The Switchres app is a bit outdated, you have a newer version here, although it doesn't support dotclockmin either.

The easiest way to force that is to use super resolutions in mame.ini. Just set "resolution 2560x0" and "cleanstretch 2".

As for the desktop, you'll need to create a modeline manually. Notice that the Switchres version linked above allows you to create a custom EDID override, for the modeline that you like. You can just create 1280x280 via Switchres and this will produce a proper EDID override which you can add to your Arch installation so it will boot using that resolution natively.

[kokoko3k]

Thanks for the edid hint!

i can confirm that my arcade monitor doesn't support other than 15/16khz.
(I tried the new switchres version, but quoted the code of the old one.)

As for the mame.ini, doesn't that method solve that issue just for the mame emulator and leave all the other emulators "out"?
Correct me if i'm wrong, but if switchres could support another switch like the -mindotclock, wouldn't that be useful for  the whole GroovyArcade live distro + netbook users or, more generally, users with "unsupported videocards" that cannot produce such low clock modelines?

Meanwhile, i'll try to understand if there is a way to simulate -mindotclock by tweaking custom monitor parameters.

[Calamity]

Thanks for the edid hint!

i can confirm that my arcade monitor doesn't support other than 15/16khz.
(I tried the new switchres version, but quoted the code of the old one.)

As for the mame.ini, doesn't that method solve that issue just for the mame emulator and leave all the other emulators "out"?
Correct me if i'm wrong, but if switchres could support another switch like the -mindotclock, wouldn't that be useful for  the whole GroovyArcade live distro + netbook users or, more generally, users with "unsupported videocards" that cannot produce such low clock modelines?

Meanwhile, i'll try to understand if there is a way to simulate -mindotclock by tweaking custom monitor parameters.

As I said the easier way to mimick the dotclock_min functionality is to simply force a wide enough resolution. This by the way is what you want to do to run Mednafen for Megadrive/SNES (and the default configuration as it is in the live-cd).

Of course it would be nice that Switchres had that feature in working order, but keep in mind it needs to be rewritten eventually to adapt it to the current Switchres engine used by GM, so it will happen at that point.