SDMA can randomly hang on Polaris 10. Hard to reproduce,
but has been occurring sporadically in the Mesa CI
on the RADV Polaris 10 job even when Mesa isn't using
the SDMA engine.
When Mesa actually uses the SDMA on Polaris, the hang
becomes more frequent and the reproduction rate goes up
significantly in the CI system.
We don't know why the hangs occur, but it seems
that inserting a single NOP packet before each
POLL_REGMEM and FENCE packet works around it.
At the moment it's unclear which GPUs are affected,
so let's apply this to SDMA 3.x for now.
Note that this issue is not documented or acknowledged by AMD.
Reviewed-by: Alex Deucher <[email protected]>
Signed-off-by: Timur Kristóf <[email protected]>
Signed-off-by: Alex Deucher <[email protected]>
(cherry picked from commit c343a27ed90823d08de125f7c447d96d056b75d9)
Cc: [email protected]
Timur Kristóf
752480ad62