Re: [PATCH] firmware: arm_scmi: fix timeout value for send_message

From: Jassi Brar
Date: Wed Jun 10 2020 - 22:46:11 EST


On Wed, Jun 10, 2020 at 10:56 AM Sudeep Holla <sudeep.holla@xxxxxxx> wrote:

[I admit you can write bigger posts than me, so I am not going to
write a passionate response to each of your paragraphs.
Let's keep it to the point.]

> > > > if (xfer->hdr.poll_completion) {
> > > > - ktime_t stop = ktime_add_ns(ktime_get(), SCMI_MAX_POLL_TO_NS);
> > > > + ktime_t stop = ktime_add_ns(ktime_get(), 500 * 1000 * NSEC_PER_USEC);
> > > >
> > >
> > > This is unacceptable delay for schedutil fast_switch. So no for this one.
> > >
> > Increasing timeout does not increase latency.
>
> Agreed, but worst case you may be stuck here for 500ms which is not
> acceptable.
>
Not acceptable to who, you or the kernel? :) Now that you said you
are fixing the scmi's fast_switch implementation.

Even though I don't think 500ms would ruin our lives, but ok, I will
make it 30ms - same as you did in the 'else' block. And drop the other
change.

Thanks.