Re: Amiga screen modes in wscons

[Carlos Milán Figueredo <cmilanf%hispamsx.org@localhost>]

Hi Michael!

From: port-amiga-owner%NetBSD.org@localhost <port-amiga-owner%NetBSD.org@localhost> on behalf of Michael van Elst <mlelstv%serpens.de@localhost>
Sent: Friday, November 10, 2023 13:49
 
>>Hi everyone!
>>Is there a way to change the screen mode used by wscons at boot time?

>I don't think so.

Thanks to your guidance I understand why :)

> It's possible that a kernel compiled without option GRF_AGA_VGA
> works better for you.

That would probably have the same effect as not using -A (that works well for me), without leaving behind AGA support, it would be a nice solution. I will give a try to compile my own kernel.

> The code for setting up the graphics is in sys/arch/amiga/dev/grfabs_cc.c:

> /* static, so I can patch and play */

> #ifdef GRF_AGA_VGA
> int     pAGA_htotal  = 0x079;
> int     pAGA_vtotal  = 0x24d;
> int     pAGA_vbstop  = 0x019;
> int     pAGA_hcenter = 0x04b;
> #else
> int     pAGA_htotal  = 0x081;
> int     pAGA_vtotal  = 0x23d;
> int     pAGA_vbstop  = 0x017;
> int     pAGA_hcenter = 0x04f;
> #endif
> int     pAGA_hsstrt  = 0x00f;
> int     pAGA_hsstop  = 0x019;
> int     pAGA_hbstrt  = 0x001;
> int     pAGA_hbstop  = 0x021;
> int     pAGA_vsstrt  = 0x001;
> int     pAGA_vsstop  = 0x008;
> int     pAGA_vbstrt  = 0x000;

> So you could also patch the kernel binary instead of recompiling.

This is really nice! I can probably solve the problem without giving up the GRF_AGA_VGA playing a bit with htotal and hcenter, just enough to get the column I am not able to display. However I have no clue on how to apply the patch to the binary file. I think I can compile my own kernel with different values and make a diff with the original one, but is there an easier way or documented procedure?

Regards,
Carlos