From: Nicholas Piggin <npiggin@gmail.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev@lists.ozlabs.org, skiboot@lists.ozlabs.org
Subject: Re: [PATCH v2 4/9] powerpc/powernv: OPAL console standardise OPAL_BUSY loops
Date: Mon, 9 Apr 2018 16:13:42 +1000 [thread overview]
Message-ID: <20180409161342.02f41b8a@roar.ozlabs.ibm.com> (raw)
In-Reply-To: <1523253213.11062.7.camel@kernel.crashing.org>
On Mon, 09 Apr 2018 15:53:33 +1000
Benjamin Herrenschmidt <benh@kernel.crashing.org> wrote:
> On Mon, 2018-04-09 at 15:24 +1000, Nicholas Piggin wrote:
> > Convert to using the standard delay poll/delay form.
> >
> > The console code:
> >
> > - Did not previously delay or sleep in its busy loop.
> >
> > Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
> > Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
>
> Does it help with anything ? We don't technically *have* to delay or
> wait, I thought it would be good to try to hit the console as fast as
> possible in that case...
We can always make exceptions to the standard form, but in those
cases I would like to document it in the OPAL API and comment for
the Linux side.
My thinking in this case is that it reduces time in firmware and
in particular holding console locks. Is it likely / possible that
we don't have enough buffering or some other issue makes it worth
retrying so quickly?
Thanks,
Nick
next prev parent reply other threads:[~2018-04-09 6:13 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-09 5:24 [PATCH v2 0/9] first step of standardising OPAL_BUSY handling Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 1/9] powerpc/powernv: define a standard delay for OPAL_BUSY type retry loops Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 2/9] powerpc/powernv: OPAL RTC driver standardise OPAL_BUSY loops Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 3/9] powerpc/powernv: opal_put_chars partial write fix Nicholas Piggin
2018-04-09 5:50 ` Benjamin Herrenschmidt
2018-04-09 5:24 ` [PATCH v2 4/9] powerpc/powernv: OPAL console standardise OPAL_BUSY loops Nicholas Piggin
2018-04-09 5:53 ` Benjamin Herrenschmidt
2018-04-09 6:13 ` Nicholas Piggin [this message]
2018-04-09 8:22 ` Benjamin Herrenschmidt
2018-04-09 5:24 ` [PATCH v2 5/9] powerpc/powernv: OPAL platform " Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 6/9] powerpc/powernv: OPAL NVRAM driver standardise OPAL_BUSY delays Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 7/9] powerpc/powernv: OPAL dump support " Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 8/9] powerpc/xive: " Nicholas Piggin
2018-04-09 5:24 ` [PATCH v2 9/9] powerpc/powernv: opal-kmsg standardise OPAL_BUSY handling Nicholas Piggin
2018-04-10 5:01 ` Russell Currey
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