From: wens@csie.org (Chen-Yu Tsai)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH 1/2] ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting
Date: Thu, 19 Mar 2015 16:17:30 +0800 [thread overview]
Message-ID: <CAGb2v656kP=+K+NCuH5hkcc4D0XhpYksbN52wZRKEVEDsBN6+w@mail.gmail.com> (raw)
In-Reply-To: <20150319085716.75d3ce76@i7>
On Thu, Mar 19, 2015 at 2:57 PM, Siarhei Siamashka
<siarhei.siamashka@gmail.com> wrote:
> On Thu, 19 Mar 2015 10:39:32 +0800
> Chen-Yu Tsai <wens@csie.org> wrote:
>
>> The Olimex A10-Lime is known to be unstable when running at 1008MHz.
>>
>> Signed-off-by: Chen-Yu Tsai <wens@csie.org>
>> ---
>> arch/arm/boot/dts/sun4i-a10-olinuxino-lime.dts | 14 ++++++++++++++
>> 1 file changed, 14 insertions(+)
>>
>> diff --git a/arch/arm/boot/dts/sun4i-a10-olinuxino-lime.dts b/arch/arm/boot/dts/sun4i-a10-olinuxino-lime.dts
>> index 31dc2f1c3870..16ecb8938e19 100644
>> --- a/arch/arm/boot/dts/sun4i-a10-olinuxino-lime.dts
>> +++ b/arch/arm/boot/dts/sun4i-a10-olinuxino-lime.dts
>> @@ -74,6 +74,20 @@
>> status = "okay";
>> };
>>
>> +&cpu0 {
>> + /* The A10-Lime is known to be unstable when running at 1008 MHz */
>> + operating-points = <
>> + /* kHz uV */
>> + 960000 1400000
>> + 912000 1400000
>> + 864000 1300000
>> + 720000 1200000
>> + 528000 1100000
>> + 312000 1000000
>> + 144000 900000
>> + >;
>> +};
>> +
>> &ehci0 {
>> status = "okay";
>> };
>
> Thanks for the patch. At least it should make my A10-OLinuXino-LIME
> working without obvious failures out of the box (the U-Boot is still
> another story though and there is a gap during boot up when the board
> is running with unreliable settings, but the probability of a failure
> is rather low).
>
> I should also mention that using 960MHz @1.4V does not fail, but it does
> not have any safety headroom either (the cyan 'sun4i_poorlime' line
> on the plot):
>
> http://people.freedesktop.org/~siamashka/files/20140512/sunxi-cpufreq-plot.png
>
> On the other hand, my board is on the worst part of the spectrum (many
> other a10-lime boards do not fail even at 1008MHz), so maybe having
> extra safety headroom is less necessary.
>
> An interesting question is whether the same problem may be reproducible
> on the Allwinner A10 devices other than A10-OLinuXino-LIME. My original
> problem report
>
> https://www.mail-archive.com/linux-sunxi at googlegroups.com/msg04343.html
>
> mentioned the A10-OLinuXino-LIME rev.A and introduced some sort of
> a bias by itself. At least I have seen people saying something like
> "my a10-lime revision is not rev.A, so it's none of my concern and
> I'm not going to bother running any tests". So far we have accumulated
> reports from 4 or 5 people having this reliability problem on their
> A10-OLinuXino-LIME (various revisions, not just rev.A), but not
> much from the other boards owners.
>
> Anyway, this particular patch is
> Tested-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
> Acked-by: Siarhei Siamashka <siarhei.siamashka@gmail.com>
Good to hear it works. Did you test all the settings? I copied the
wrong settings, from sun5i-a13.dtsi instead of sun4i-a10.dtsi.
I'll send a fixed version later.
ChenYu
next prev parent reply other threads:[~2015-03-19 8:17 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-19 2:39 [PATCH 0/2] ARM: dts: sunxi: Fix cpufreq instabilities Chen-Yu Tsai
2015-03-19 2:39 ` [PATCH 1/2] ARM: dts: sun4i: a10-lime: Override and remove 1008MHz OPP setting Chen-Yu Tsai
2015-03-19 6:57 ` Siarhei Siamashka
2015-03-19 8:17 ` Chen-Yu Tsai [this message]
2015-03-19 10:28 ` Siarhei Siamashka
2015-03-26 16:58 ` [linux-sunxi] " Iain Paton
2015-03-26 17:56 ` Chen-Yu Tsai
2015-03-19 2:39 ` [PATCH 2/2] ARM: dts: sunxi: Remove overclocked/overvoltaged OPP Chen-Yu Tsai
2015-03-19 6:59 ` Siarhei Siamashka
2015-03-19 7:11 ` Chen-Yu Tsai
2015-03-19 8:14 ` Chen-Yu Tsai
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