[PATCH 2/6] xfree86: Drop DDC1 support

Mark Kettenis mark.kettenis at xs4all.nl
Fri Dec 2 09:01:25 PST 2011

> From: Adam Jackson <ajax at redhat.com>
> Date: Thu,  1 Dec 2011 16:50:57 -0500
> This was an ancient hack to try to fetch the EDID block by reusing the
> vertical sync pin as a serial line.  It's never been very reliable, and
> DDC2 was introduced in 1994 which is plenty recent enough.

Hmm, if Wikipedia is to be believed DDC1 and DDC2 were actually both
introduced at the same time (in 1994).  And there was a dedicated pin
for it; vertical sync was just used for the clock.  DDC1 support in
the graphics cards seemed to be quite widespread judging from the open
source drivers, but it is effectively disabled in several drivers, and
most, if not all, also try to support DDC2.  So I can support getting
rid of DDC1 support.  However, rather than breaking drivers, can we
just replace xf86DoEDID_DDC1() with a dummy version that prints a
warning message and just returns NULL?  That should keep drivers from

> Signed-off-by: Adam Jackson <ajax at redhat.com>
> ---
>  hw/xfree86/ddc/ddc.c        |  216 -------------------------------------------
>  hw/xfree86/ddc/xf86DDC.h    |   14 ---
>  hw/xfree86/modes/xf86Crtc.c |    1 -
>  hw/xfree86/vgahw/vgaHW.c    |   94 -------------------
>  hw/xfree86/vgahw/vgaHW.h    |    2 -
>  5 files changed, 0 insertions(+), 327 deletions(-)

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