On Fri, Aug 13, 2021 at 2:57 PM Yong Wu [off-list ref] wrote:

Prepare for 2 HWs that sharing pgtable in different power-domains.

The previous SoC don't have PM. Only mt8192 has power-domain,
and it is display's power-domain which nearly always is enabled.

When there are 2 M4U HWs, it may has problem.
In this function, we get the pm_status via the m4u dev, but it don't
reflect the real power-domain status of the HW since there may be other
HW also use that power-domain.

Currently we could not get the real power-domain status, thus always
pm_runtime_get here.

Prepare for mt8195, thus, no need fix tags here.

This patch may drop the performance, we expect the user could
pm_runtime_get_sync before dma_alloc_attrs which need tlb ops.

Can you check if there are existing users that need to add this change?

Signed-off-by: Yong Wu <yong.wu@mediatek.com>
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