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Message-ID: <CAMuHMdXCn-tKcaeAHTgdJu0Lg=YrF7cFnW8-tD4ZBfVPUb53NA@mail.gmail.com>
Date: Mon, 4 Jan 2021 09:18:43 +0100
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Daniel Lezcano <daniel.lezcano@...aro.org>
Cc: "Rafael J. Wysocki" <rafael@...nel.org>,
Linux PM list <linux-pm@...r.kernel.org>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
kernel test robot <lkp@...el.com>,
"Rafael J. Wysocki" <rjw@...ysocki.net>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] powercap/drivers/dtpm: Fix __udivdi3 and __aeabi_uldivmod
unresolved symbols
Hi Daniel,
On Wed, Dec 30, 2020 at 4:39 PM Daniel Lezcano
<daniel.lezcano@...aro.org> wrote:
> 32 bits architectures do not support u64 division, so the macro
> DIV_ROUND_CLOSEST is not adequate as the compiler will replace the
> call to an unexisting function for the platform, leading to an
> unresolved symbols.
>
> Fix this by using the compatible macros:
>
> DIV64_U64_ROUND_CLOSEST and DIV_ROUND_CLOSEST_ULL.
>
> Reported-by: kernel test robot <lkp@...el.com>
> Signed-off-by: Daniel Lezcano <daniel.lezcano@...aro.org>
Thanks for your patch!
> --- a/drivers/powercap/dtpm.c
> +++ b/drivers/powercap/dtpm.c
> @@ -99,8 +99,8 @@ static void __dtpm_rebalance_weight(struct dtpm *dtpm)
> pr_debug("Setting weight '%d' for '%s'\n",
> child->weight, child->zone.name);
>
> - child->weight = DIV_ROUND_CLOSEST(child->power_max * 1024,
> - dtpm->power_max);
> + child->weight = DIV64_U64_ROUND_CLOSEST(
> + child->power_max * 1024, dtpm->power_max);
Note that 64-by-64 divisions are expensive on 32-bit platforms.
Does dtpm.power_max need to be u64?
The (lack of) documentation for the dtpm structure does not say what is
being stored there.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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