Mikko Perttunen e19e56a251 gpu: host1x: Remove mid-job CDMA flushes ...

The current code can issue CDMA flushes (DMAPUT bumps) in the middle
of a job, before all opcodes have been written into the pushbuffer.
This can happen when pushbuffer fills up. Presumably this made sense
at some point in the past, but it doesn't anymore, as it cannot lead
to more space appearing in the pushbuffer as it is only cleaned full
jobs at a time.

Mid-job flushes can also cause problems, as in an extreme situation
(seen in practice), the hardware can run through the entire pushbuffer
including the prefix of a partially written job without the driver
being able to process any CDMA updates. This can cause the engine
MLOCK to be taken and held for extended periods as the tail of the
job is not yet available to hardware.

Bug 4606343

Signed-off-by: Mikko Perttunen <mperttunen@nvidia.com>
Change-Id: I68ca317150e917428d757d4ee8a68c2c15eaf8de
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nv-oot/+/3186138
GVS: buildbot_gerritrpt <buildbot_gerritrpt@nvidia.com>
Reviewed-by: Santosh BS <santoshb@nvidia.com>

2024-08-06 15:51:12 -07:00

16 KiB

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