Re: [AD] [LINUX] VGA/ModeX drivers

["Eric Botcazou" <ebotcazou@xxxxxxxxxx>]

> This is what happens on my machine (nViDiA tNT2).

Here are the results on mine (ATI Xpert@xxxxxxxxxx 98).

> Firstly, under text mode.
>
> The vga/modex drivers work, but have trouble when the svgalib driver
> is involved.  This isn't always obvious, e.g. when the mode selector
> dialog is run, it has to start up svgalib to get video modes.  The VT
> gets wedged after exiting from the mode selector dialog.  To confirm,
> programs using the mode selector dialog work when the svgalib module
> is removed from modules.lst.

No problems for VGA/ModeX with or without SVGAlib, neither in a console nor
in a VT.

However, I consistently get a SIGSEGV on exiting the demo program with
SVGAlib, but only in a console (not in a VT) and only if modules are
enabled, normal or debug build (if modules are disabled, no SIGSEGV but the
prompt doesn't display the typed keys any longer).

And GDB doesn't help very much:
[Switching to Thread 1024 (LWP xxxxx)]
xxxxxxxxx in ?? ()
backtrace
#0 xxxxxxxxxx in ?? ()
#1 xxxxxxxxxx in __libc_start_main()

> Unless someone can be bothered figuring out what's going on, I propose
> that the svgalib mode fetching code be disabled.  It would be possible
> to reenable it after 4.0 without breaking ABI compatibility.

Sounds sensible to me.

> Now, under fbcon (vesafb).

vesafb 1024x768x16

> It doesn't work.  Svgalib's VGA driver doesn't work right either, so
> maybe it's not our fault.  The easiest thing is probably to make
> vga/modex a module then tell fbcon users to remove the module and use
> the svgalib driver (assuming the above problem is dealt with).

Same thing: VGA doesn't work.
And SVGAlib sort of works: the colors are all screwed up in the demo game.

--
Eric Botcazou
ebotcazou@xxxxxxxxxx