[OpenJDK 2D-Dev] RFR: 8252133 The java/awt/GraphicsDevice/DisplayModes/CycleDMImage.java fails if metal pipeline is active

Sergey Bylokhov Sergey.Bylokhov at oracle.com
Sun Aug 30 00:29:44 UTC 2020

Please review the fix for jdk/client.

Bug: https://bugs.openjdk.java.net/browse/JDK-8252133
Fix: http://cr.openjdk.java.net/~serb/8252133/webrev.00

This bug easily reproduced by the test in question on the dual video card systems
when the metal pipeline is active. But it is possible to reproduce it in the OGL
pipeline as well, but it is required some additional steps.

Problem description:
   Our CGraphicsEnvironment maintains the list of active graphics devices. The one
important feature of this CGraphicsEnvironment is to invalidate the old devices and
map them to the new devices. For example, if the user got a reference to the device,
and this device was removed then this reference will refer to the main screen.

The problem in the current implementation arise when the system has two video cards:
  1 The user get some GraphicsDevice
  2 The user sets the full-screen window for this device
  3 The user change screen resolution for this device
  4 The resolution of the screen is not changed ->> BUG.

The problem is that somewhere after step 1 or 2 and before step 3 the macOS decided
to switch to the discrete video card, but it does not report the old device(integrated VC)
as removed, because actually no screens were removed.

Since it was not reported as removed we did not invalidate it and did not map it to the
new device ->> request to change the screen resolution at step 3 send to some non existed

As a fix I suggest to change this logic:
  - Invalidate devices reported by macOS as removed
  - Initialize the main screen
  - Initialize all NEW screens

To this logic:
  - Ignore devices reported by the macOS as removed
  - Initialize the main screen
  - Initialize all NEW screens
  - Check that the main device is in the list of all NEW devices
  - Invalidate all OLD devices which are not in the list of NEW devices

Best regards, Sergey.

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