Re: [AD] 'teensy little change' to fbcon.c fixes allegro-4.0.3 to work on my stupid platform

[Eric Botcazou <ebotcazou@xxxxxxxxxx>]

> however, until this morning, i was unable to get an appropriate display
> until i hacked the 'stride' assignment to use the fb fixedinfo
> line_length instead of my_mode.xres_virtual:
>
> roughly line 276 in src/linux/fbcon.c...
>
> /* stride = my_mode.xres_virtual * BYTES_PER_PIXEL(color_depth); */
>
> stride = fix_info.line_length * BYTES_PER_PIXEL(color_depth);
>
> It works for me on my challenged platform, and i suspect that it might
> be a generally applicable fix.

I think you're very likely right. It Works For Me(tm) too.

> However, it begs the question of why it was coded that way in the first
> place.

Over-simplification I'd say.

> Does it work properly as originally coded on somebody else's platform?

You're the only one to report the problem AFAIK.

> If the original code *does* work properly for somebody else, i'd like
> to hear about it, because it will probably give me a new understanding
> about how framebuffer is supposed to work.

I guess the VRAM layout is dependent upon the graphics card. The original 
code was probably good enough for the majority of cards, but not for yours.

> If it's a generally applicable fix, i'd love to see it added, if it's
> not, i'd really love to hear about why it isnt.

I'm not a specialist of the Linux framebuffer, but your fix seems highly 
sensible to me. If nobody opposes, I'll apply it to the 4.0.x and 4.1.x 
series.

Thanks!

-- 
Eric Botcazou