linux-kernel - Re: [PATCH 1/3] x86: ce4100: implement pm

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20121026093026.GA1106@gmail.com>
Date:	Fri, 26 Oct 2012 11:30:26 +0200
From:	Ingo Molnar <mingo@...nel.org>
To:	Florian Fainelli <ffainelli@...ebox.fr>
Cc:	tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
	rui.zhang@...el.com, alan@...ux.intel.com,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/3] x86: ce4100: implement pm_poweroff


* Florian Fainelli <ffainelli@...ebox.fr> wrote:

> The CE4100 platform is currently missing a proper pm_poweroff implementation
> leading to poweroff making the CPU spin forever and the CE4100 platform does
> not enter a low-power mode where the external Power Management Unit can
> properly power off the system. Power off on this platform is implemented pretty
> much like reboot, by writing to the SoC built-in 8051 microcontroller mapped at
> I/O port 0xcf9, the value 0x4.
> 
> Signed-off-by: Florian Fainelli <ffainelli@...ebox.fr>
> ---
>  arch/x86/platform/ce4100/ce4100.c |    7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/arch/x86/platform/ce4100/ce4100.c b/arch/x86/platform/ce4100/ce4100.c
> index 4c61b52..74f8774 100644
> --- a/arch/x86/platform/ce4100/ce4100.c
> +++ b/arch/x86/platform/ce4100/ce4100.c
> @@ -27,6 +27,11 @@ static int ce4100_i8042_detect(void)
>  	return 0;
>  }
>  
> +static void ce4100_power_off(void)
> +{
> +	outb(0x4, 0xcf9);

Would be nice to precede this function with something like:

/*
 * Power off on this platform is implemented pretty
 * much like reboot, by writing to the SoC built-in
 * 8051 microcontroller mapped at I/O port 0xcf9,
 * the magic value 0x4:
 */
static void ce4100_power_off(void)
{
	outb(0x4, 0xcf9);
...

As arguably such comments are even more useful in the code than 
in a changelog.

Thanks,

	Ingo
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/