From: Viresh Kumar <viresh.kumar@linaro.org>
To: Sudeep Holla <sudeep.holla@arm.com>
Cc: "Rafael J . Wysocki" <rjw@rjwysocki.net>,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH] cpufreq: mark duplicate frequencies as invalid and continue as normal
Date: Wed, 23 Oct 2019 08:56:08 +0530 [thread overview]
Message-ID: <20191023032608.v7lgqirvpbwgsyz4@vireshk-i7> (raw)
In-Reply-To: <20191022173215.13350-1-sudeep.holla@arm.com>
On 22-10-19, 18:32, Sudeep Holla wrote:
> Currently if we encounter duplicate frequency table entries, we abort
> the validation and return error immediately. Instead of failing, we
> can mark the entry as invalid and continue to function normal.
>
> Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
> ---
> drivers/cpufreq/freq_table.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> Hi Viresh,
>
> Since commit da0c6dc00c69 ("cpufreq: Handle sorted frequency tables more
> efficiently"), I seem to have modified the firmware entry on my TC2 to
> drop 500MHz and had not seen the issue with duplicate entries and had
> totally forgotten about it.
>
> Recently I reverted back to original setting as I corrupted it and
> started seeing this issues. I don't know the background for raising
> duplicates as fatal error but we did allow it when we add arm_big_little.c
> and hence this RFC. If there are known issues with this approach, I can
> continue with changed firmware config.
>
> With switcher, we have:
> (little cluster)
> Virt: 175 MHz, 200 MHz, 250 MHz, 300 MHz, 350 MHz, 400 MHz, 450 MHz, 500 MHz
> Actu: 350 MHz, 400 MHz, 500 MHz, 600 MHz, 700 MHz, 800 MHz, 900 MHz, 1000 MHz
> (big cluster)
> 500 MHz, 600 MHz, 700 MHz, 800 MHz, 900 MHz, 1000 MHz, 1.10 GHz, 1.20 GHz
>
> with 500 MHz duplicate in merged table.
>
> Regards,
> Sudeep
>
> diff --git a/drivers/cpufreq/freq_table.c b/drivers/cpufreq/freq_table.c
> index ded427e0a488..e9bf287846d6 100644
> --- a/drivers/cpufreq/freq_table.c
> +++ b/drivers/cpufreq/freq_table.c
> @@ -305,9 +305,10 @@ static int set_freq_table_sorted(struct cpufreq_policy *policy)
> }
>
> if (pos->frequency == prev->frequency) {
> - pr_warn("Duplicate freq-table entries: %u\n",
> + pr_warn("Duplicate freq-table entries: %u marking it invalid\n,",
> pos->frequency);
> - return -EINVAL;
> + pos->frequency = CPUFREQ_ENTRY_INVALID;
> + continue;
> }
>
> /* Frequency increased from prev to pos */
Of course we can do this, but I don't see why we shouldn't force
people to fix the freq-tables instead. What's the point of allowing
people to have duplicate entries instead ? This shouldn't happen with
OPP tables as we check for duplicate entries there as well.
--
viresh
next prev parent reply other threads:[~2019-10-23 3:26 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 17:32 [RFC PATCH] cpufreq: mark duplicate frequencies as invalid and continue as normal Sudeep Holla
2019-10-23 3:26 ` Viresh Kumar [this message]
2019-10-23 9:06 ` Sudeep Holla
2019-10-23 9:14 ` Viresh Kumar
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191023032608.v7lgqirvpbwgsyz4@vireshk-i7 \
--to=viresh.kumar@linaro.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rjw@rjwysocki.net \
--cc=sudeep.holla@arm.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).