Can't set attribute auto_refresh after reinitializing display

[FoamyGuy]

Adafruit CircuitPython 10.0.0-alpha.2-36-g53a856b67a on 2025-04-23; Adafruit Fruit Jam with rp2350b

reinit_display.py:

from displayio import release_displays
import picodvi
import board
import framebufferio

SIZE = (640, 480)

# initialize display
release_displays()

fb = picodvi.Framebuffer(
    SIZE[0],
    SIZE[1],
    clk_dp=board.CKP,
    clk_dn=board.CKN,
    red_dp=board.D0P,
    red_dn=board.D0N,
    green_dp=board.D1P,
    green_dn=board.D1N,
    blue_dp=board.D2P,
    blue_dn=board.D2N,
    color_depth=8,
)
display = framebufferio.FramebufferDisplay(fb)

# display.auto_refresh = False
# print("after set auto refresh")

set_auto_refresh.py:

import supervisor
display = supervisor.runtime.display
display.auto_refresh = False

If I run these two scripts back to back in the REPL they raise an exception about not being able to set auto_refresh on the display.

>>> import reinit_display
>>> import set_auto_refresh
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "set_auto_refresh.py", line 3, in <module>
AttributeError: can't set attribute 'auto_refresh'

If I un-comment the line setting auto_refresh in the reinit_display.py that one does seem to succeed and does not raise the exception. Only when trying to set the auto_refresh from another file it raises this exception.

[tannewt]

I think this is intended now. supervisor.runtime isn't reset when the display is reinit. So, you are trying to set the attribute on the None object.

[FoamyGuy]

Is it possible to access the manually initialized display any time after the code file that initialized it is complete?

If it's not possible I think it poses some challenges like if the code that initialized it set auto_refresh to False then it will be stuck in that state until re-initialized again.

Or for the launcher -> app -> back to launcher flow, if the app were to manually re-init the display then when the launcher takes back over it won't be able to set the new root_group. I think launcher and other display apps may need to always test for None and then handle initialization manually perhaps.

[FoamyGuy]

Oh! I see now that you can set supervisor.runtime.display = display also which makes this work how I was thinking that it would before.