Found bug in mode switching but who is at fault...XFree86 or aty128fb.c?

[Geert Uytterhoeven]

On Fri, 24 Mar 2000, Kevin Hendricks wrote:
> Okay so I found the bug.  It seems all through the r128 driver, crtc.pitch
> values are set to the virtual x resolution  (vxres) / 8.  But in aty128fb.c in
> the var_to_crtc routine the crtc.pitch is set to be just the xres / 8.

Which is wrong: aty128fb must do `vxres * bpp / 8'.

> Who is wrong?  Should xfree shrink the vxres and vyres to match xres and yres
> before calling set_var or should aty128fb.c var_to_crtc routine be fixed to use
> vxres >> 3 instead of just xres >> 3?

XFree86 cannot change the visible resolution on the fly.

> What use is it to get a nice 832x624 hole into a display that is virtually
> 1152x870?!?  I can't get to any of the kde controls, panels, etc since they are
> off the screen!  And it would be a pain to have to pan around looking for them
> (especially since the ioctl for panning is on the "to do" list!).

Hence panning needs to be fixed :-) In fact panning is very simple, just change
the offset of the first pixel. That's a `one-register' update.

> So my feeling is that both are wrong.  We should shrink the virtual resolution
> to match the physical resolution in xfree when mode switching and put the patch
> in place in aty128fb.c

XFree86 cannot change the visible resolution on the fly, so we cannot change
it. Design bug in the whole X system :-)

Gr{oetje,eeting}s,

						Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
							    -- Linus Torvalds


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