[PATCH 2/2] mailbox: mtk-cmdq: Move pm_runimte_get and put to mbox_chan_ops API

[Jassi Brar]

On Tue, Jun 18, 2024 at 3:42 AM Jason-JH Lin (林睿祥)
<Jason-JH.Lin at mediatek.com> wrote:
>
> On Mon, 2024-06-17 at 13:18 -0500, Jassi Brar wrote:
> >
......

> > As in, how often and long are the "channel idle" periods? And when
> > active, how many transfers/sec ?
> Is there any debug logs in mailbox can measure this?
>
> This mailbox channel is use to configure display hardware in every
> VSYNC, so the channel idle periods may be less than 16.66ms.
>
> It should call rx_callback() before VACTIVE, but sometimes it will be
> dropped by mbox_flush() if the new message is coming.
>
> > I see every TX is acked by one RX packet. How long is the typical gap
> > between a TX and its ack?
>
> Typical gap between a TX and its ack is less than 16.66ms.
>
So basically the usecase is driving some display at 60Hz. And I
believe the display is driven
continuously for at least some minutes ?
If so, RPM between xfers is not really in effect because the
autosuspend delay is 100ms while you
get() it every 16.66ms. So all that is happening is some variables
changed under a spinlock.
I think you should consider get/put RPM in cmdq_mbox_startup() and
cmdq_mbox_shutdown().

Thanks