[PATCH] gpu: host1x: Remove mid-job CDMA flushes

[Thierry Reding]

On Tue, Feb 04, 2025 at 02:45:46AM +0000, Mikko Perttunen wrote:
> 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.
> 
> Signed-off-by: Mikko Perttunen <mperttunen at nvidia.com>
> ---
>  drivers/gpu/host1x/cdma.c | 7 +------
>  1 file changed, 1 insertion(+), 6 deletions(-)

Applied, thanks.

Thierry
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