[Xorg-driver-geode] looking at wide mode support for GeodeLX (continued)

[Bart Trojanowski]

So I returned to looking into the missing modes on the GeodeLX.  This
work is funded by symbio-technologies.com -- thanks.

At this time I don't have a patch because my code is still a mess with
debug code, but it's eminent.  The changes will be restricted to the
amd_lx_driver.c file in the -amd driver.

In order to get wide modes two things need to happen:

1) LXValidMode() currently calls vg_get_display_mode_index() to find a
    mode that X wants validated a CimarronDisplayModes[] table kept in
    src/cim/cim_modes.c.  The problem here is that this table contains
    nothing a wide LCD monitor would display natively.

    I fixed this by cutting out the check; that is removed the call to
    vg_get_display_mode_index() and just return MODE_OK if it's non-PANEL
    output.  I'll still call vg_get_display_mode_index(), but only report
    if the check fails... and continue on.

    I have no idea what implications using non-Cimarron modes has.  I
    don't even know what Cimarron modes are :) ... so I would like for
    someone (Jordan, Martin-Eric) to comment before I make CRTs explode.

2) LXSetVideoMode() is called to switch to a new mode (either the
    initial one, or later with xrandr or Ctrl-Alt-+/-).

    If the mode is specified from xorg.conf we get a flag indicating
    that this is a M_T_USERDEF mode and call lx_set_custom_mode() and
    everything works fine (almost, see below).

    If the mode is detected by X, then vg_set_display_mode() is called.
    This code path checks for a valid mode in the CimarronDisplayModes[]
    table and just fails.

    It so happens that while vg_set_display_mode() returns an error, we
    never checked for it.  I have added this code:

        rc = vg_set_display_mode( ... );
        if (rc)
                lx_set_custom_mode( ... );
                // I plan to report if this call fails :)

    and I can get X to display any mode upto 1600x1200.  It even thinks
    that it can do 1920x1200.

It's *almost* perfect...

The native mode on my new monitor is 1920x1200, which the DDC reports
and the LX happily provides.  The screen is rendered, and at first I
thought it was working.  However it seems that the display is actually
rendering at 1600x1200, while the buffer is 1920x1200.  

If X was aware of this, it would pan when I moved the mouse to the edge,
but the cursor just goes off screen.  Even xrandr reports that it's set
to 1920x1200, and doesn't even list 1600x1200 as an alternative (BTW, I
can have it display 1600x1200 if I set such a "Modes" line in xorg.conf).

I think it's the Geode that's doing this reduction.  Thoughts?

-Bart

-- 
				WebSig: http://www.jukie.net/~bart/sig/