>
> Not every machine has a BIOS.
In that case, there are a few more things (in addition to panel size) we
need to worry about before it can work reliably. Things like PLL ref clock,
display type ... are all derived from video BIOS image.

> > As for non-native modes (resolution lower than panel size), by default,
> > radeon driver will use the internal ratio matrix expansion (RMX) unit to
> > scale the display down. It works not only for all standard VESA modes,
it'll
> > work also for any mode between 320x200 and panel size, for example
600x500.
>
> That was just an example why using virtual resolution as panel size
> doesn't work in general.
Virtual resolution should not be used as panel size, it never has.

> > Is the DDC detection OK?
>
> No, because we don't have a way to determine the display type yet (do
> you happen to know a way which doesn't require a BIOS?). If I hardcode
>
> info->DisplayType = MT_LCD;
> info->DDCType = DDC_DVI;
>
> DDC works (nice!), but there's still the same flicker. Option "DDCModes"
> isn't used, but I assume not providing any Modes is mostly the same.

I took a shortcut in determining the display type -- thru video BIOS
settings. It works in most of cases, but not really reliable as seen in your
case (I have comments on this inside the code, I think). A more proper way
to enumerate through all DDC types and probe potential connected monitors.
Once you have EDID data, you can derive its display type. This should work
in your case. But, in general, you cannot conclude there is no display
connected if the DDC detection fails. A lot of laptop panels simply are not
DDC capable, the panel info is hardcoded into the BIOS image (this may not
apply to you). The combination of two methods will make the auto-detection
more reliable.

As for the flicker problem, maybe you can print out all PLL parameters and
CRTC settings used by driver and compare them with the settings used for
FBDev. If the driver cannot access BIOS, it'll use the hardcoded PLL
parameters, I'm not sure if they are correct in your case.

Hui

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