glx apps with dri2 lock up display with xserver 1.20.1
This locks up the X display with no error in Xorg.log or dmesg when using modesetting driver with glamor:
Only cursor is visible but display becomes unresponsive. glxgears with DRI3 doesn't lead to such a problem. This also means that applications using vaapi sink (which is DRI2) don't work with glx.
I did a bisect and the bad commit is:
glamor: Reallocate pixmap storage without modifiers if necessary If we need a pixmap's storage to be exported to a context in which we aren't aware of modifiers, reallocate the buffer again without modifiers. This makes it possible to run a compositing manager on an old GLX/EGL stack on top of an X server which allocates internal buffer storage using exotic modifiers from modifier-aware GBM/EGL/KMS.
Using Intel DDX driver works. Disabling glamor also works. GBM_BO_WITH_MODIFIERS is 1.