By adding a new output callback, ->get_crtc, xf86SetDesiredModes is able to
avoid turning off outputs & CRTCs if the current output<->CRTC mappings are the
same as the desired configuration. This helps avoid flickering displays at
startup time, which speeds things up a little and looks better.
Unless we check for vtSema before calling into the CRTC and output callbacks,
we may end up trying to access video memory that no longer exists, leading to a
crash. So if we don't have vtSema, return FALSE to the caller, indicating that
we didn't do anything.
Fixes#14444.
Actually more like in the mainline case, where the ideal mode happens to
be the very first aspect match on the first monitor. But let's not
split hairs.
While the ScreenRec's notion of size in millimeters would get updates,
the RANDR 1.1 notion wouldn't, so your screen would appear to be square
and probably at some ludicrous DPI.
i.e., don't check for the end of the list by ->name == NULL, since that
won't work now. Fix the consumers of xf86DefaultModes to use the new
explicit size as well.
In order to report accurate values to users of the RandR property interface,
it's sometimes necessary to ask the driver to update the value (for example
when backlight brightness changes without the server's knowledge, due to hotkey
events or direct sysfs banging).
This patch wires up the core server code with a new xf86CrtcFuncs callback,
get_property, to allow for this.
The new code is available under the RANDR_13_INTERFACE define, which in turn
depends on the RANDR_12_INTERFACE code.
Old heuristic was to find the first monitor that expressed a preference,
then attempt to get all other monitors to agree. This doesn't work
particularly well when the two sets of modes don't precisely intersect,
you get overlapping-but-not-identical output geometry and things go wrong.
New heuristic is:
- Exact user preference, if given
- Exact output preference, if the same for all outputs
- Best (largest) mode of modes common to all outputs:
- with the same aspect ratio as all outputs (may be NULL)
- with 4:3 aspect ratio
- Then the old heuristic to try to get something lit
Note that it is simply not doable to have a reliable initial output guess if
you insist on trying to clone all outputs together. It's far too easy to
end up with displays that simply don't have modes in common. We need to
switch to right-of placement someday, once we're not limited to CRTC size
limits and we have working multi-GPU in RANDR.
If you don't do this, then Modes "800x600" in the Display subsection will
be dutifully ignored and the driver will start at whatever resolution it
feels like.
CVT is enough different from GTF that it should not be used on monitors
that aren't expecting it. This brings us closer to what the spec says
the correct behaviour is.
Before this it was meaningless to try to mark DisplayModeRec tables
const, since the mode name would be emitted as a pointer to an
anonymous string constant, and therefore would have to be fixed up by
ld.so and so couldn't live in .rodata. With this change the standard
mode lists can live in .rodata, and modes duplicated from them will
have their names filled in on the fly.
xf86CrtcRotate() is called by randr 1.2 drivers via xf86CrtcSetMode() or xf86SetDesiredModes()
during ScreenInit() at which point pScrn->pScreen is not set. If a user specifies a rotation
in their config file pScrn->pScreen is dereferenced and boom.