Build Your Own Arcade Controls Forum

Software Support => GroovyMAME => Topic started by: tb404 on February 14, 2017, 06:59:50 am

Title: SwitchRes and minimum Pixel-Clock 7.12MHz
Post by: tb404 on February 14, 2017, 06:59:50 am

I have a ATI Radeon X1300Pro 256MB and it has minimum Pixel-Clock 7.12MHz.

I noticed when I run certain games the screen goes out of sync.


I am using the following SwitchRes parameter:

 pal
   
      crt_range0  15625.00-15625.00, 50.00-50.00, 1.500, 4.700, 5.800, 0.064, 0.160, 1.056, 0, 0, 192, 288, 448, 576


What can one do to make sure the pixel-clock doesn't go below 7.12MHz?

I can get around this problem using Xorg custom modelines by using horizontal resolution doubling, but I'm unsure how to put that to practice using SwitchRes.

Title: Re: SwitchRes and minimum Pixel-Clock 7.12MHz
Post by: buttersoft on February 14, 2017, 06:45:22 pm

There's nothing in the range limits about the pixel clock, because the final factor is the horizontal resolution, which isn't specified there.

For windows there is however an option in both the older and the newer VMMaker to set a minimum pixel clock. If there are no modes in your system with a lower pixel clock, Switchres can't pick them. It doesn't really generate modes, it alters the timing of existing modes using the range limits. Either open vmmaker.ini for the older version, or look in the GUI under settings for the newer, which by default says "auto".

For Linux, I'd imagine it's the same in that if the modes aren't there, Switchres can't pick them? Anything on the border that has its vertical refresh altered might dip below, but a 640x240p @60 mode is 10kHz, so I don't think you'll get into trouble there.

I can't think of another way around right now. I'm not sure if you could leave Switchres active, and not use super resolutions but set the stretching options manually. I don't know what happens then. If you leave the nag screens up, I'm sure GM will tell you.

(I'm not sure dipping below the pixel clock is a sync issue per se so much as that the card simply fails to deliver anything intelligible, or defaults to a fallback mode such as 480p?)

Title: Re: SwitchRes and minimum Pixel-Clock 7.12MHz
Post by: Calamity on February 15, 2017, 01:49:03 am

There's a dotclock_min option in mame.ini. Simply use it.

Title: Re: SwitchRes and minimum Pixel-Clock 7.12MHz
Post by: tb404 on February 15, 2017, 02:52:57 pm

awesome, works!

[SOLVED]

Title: Re: SwitchRes and minimum Pixel
Post by: buttersoft on February 15, 2017, 05:06:41 pm

Hah, that was a much simpler way around :)

I hope I'm actually learning something from all this instead of merely making an idiot of myself.

Title: Re: SwitchRes and minimum Pixel
Post by: Sledge on February 15, 2017, 10:41:50 pm

Quote from: buttersoft on February 15, 2017, 05:06:41 pm

I hope I'm actually learning something from all this instead of merely making an idiot of myself.

We all do that until we learn enough :)