Re: Getting ACRN to work

Xinyun Liu

Hi Dubravko,

For cursor invisible issue, here is my understanding:
Previously, acrngt display solution is based on plane restriction feature( ), which is a hack in kernel driver i915 display module.  To make it's work,  it requires both UOS and SOS has the correct kernel parameters.  And it does work well for it's original use case: sos is clear linux with IAS ( Intel modified weston for IVI)  and uos is Android.
here is  the sample for apl_mrb: (

sos:  "i915.enable_initial_modeset=1 video=DP-1:d video=DP-2:d i915.avail_planes_per_pipe=0x01010F i915.domain_plane_owners=0x011011100000 i915.enable_guc_loadin  g=0 i915.enable_guc_submission=0 i915.enable_preemption=1 i915.context_priority_mode=2 i915.enable_gvt=1"
uos: "i915.enable_rc6=1 i915.enable_fbc=0 i915.enable_guc_loading=0 i915.avail_planes_per_pipe=0x070F00"

You can try above setting for your configuration: clearlinux + other linux. Make sure clearlinux has the duplicated mornitor setting.

And after switch to kbl/whl nuc platform, things changed.  As the default desktop env may be changed to X windows, there are some issues. For example
1. Cursor.  We haven't enabled H/W cursor plane in SOS during mode setting stage because it's not implemented according the original design.  The cursor plane could be used by App who explicity claimed.
2. Pipe A.  Currently we focus on WaaG (Windows  as a guest). Windows (and vanilar linux) kernel doesn't has plane restriction feature, and they use pipe A as the default/first output pipe. So we have to set "i915.avail_planes_per_pipe=0x000F00 i915.domain_plane_owners=0x0000001111" in SOS to let SOS use pipe B or others.  Then UOS and SOS should both have display output now but has some limitations.  Some App in SOS also select pipeA as the default output, so there is problems.
3. Mode setting.  The assumption is mode setting is done in SOS and no one should touch the pipe/crtc settings. But X and other app may explictly change the mode and cause UOS display issue.

Above are the issues I have met if SOS has a desktop environment. But for RT env, the requirement is different. Only UOS needs graphics UI and others has no output. 


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