Libtaskmanager's buffer for spa_builder is too small on certain
configurations. Because podBuilder->state.offset is never reset, the
buffer space can run out when EGL returns a long list of dma_buf
modifiers, causing PipeWire negotiation to fail.
An example is when EGL returns 20 modifiers. There are 6 formats defined
in pipewiresourcestream.cpp, for each format it will construct 2 frames,
one with 21*8=168 bytes long of modifiers. The modifier lists for all
frames will be 6*168=1008 bytes (only 16 bytes left of 1024 bytes), let
alone other frames.
BUG: 446061
There were some changes in KWin that only enabled exchanging streams
(thumbnails in our case) in case it's properly supported. We need to
explicitly request it now, otherwise we get memfd which is much slower.
We recently changed it so kwin defaults to memptr because some clients
couldn't deal with dmabuf. We still want dmabuf to be used as it's less
stressful to the system and we support it just fine.
David Edmundson
Aleix Pol
Fabian Vogt
Alexander Lohnau