drm/i915: Optimize icl+ universal plane programming
On icl+ all plane registers are armed by PLANE_SURF, so we can
move almost everything over into the update_noarm() hook.
The PLANE_CTL write has to stay in the icl_update_arm() hook though
as it still exhibits the somewhat annoying self-arming behaviour
when the plane transitioning from disabled to enabled.
We could either do a full split for skl+ vs. icl+, or we could try
some other kind of split where we'd eg. keep most things in the skl+
functions and call them from the icl+ functions. I think a full split
is probably the cleaner approach since we've anyway accumulated quite
a bit of icl+ specific things, so that is what I opted to do.
Some i915_update_info stats for tgl:
before: after:
Updates: 5043 Updates: 5043
| |
1us | 1us |
|** |***
4us |****** 4us |********
|********** |***********
16us |*********** 16us |**********
|**** |*
66us | 66us |
| |
262us | 262us |
| |
1ms | 1ms |
| |
4ms | 4ms |
| |
17ms | 17ms |
| |
Min update: 3494ns Min update: 2983ns
Max update: 49491ns Max update: 39986ns
Average update: 18031ns Average update: 13423ns
Overruns > 100us: 0 Overruns > 100us: 0
Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220210062403.18690-2-ville.syrjala@linux.intel.com
Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com>