linux-kernel - Re: [PATCH v4 6/6] hwmon: use smp_call_on

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Date:	Thu, 21 Apr 2016 15:12:52 +0200
From:	Juergen Gross <jgross@...e.com>
To:	Pali Rohár <pali.rohar@...il.com>,
	Guenter Roeck <linux@...ck-us.net>
Cc:	linux-kernel@...r.kernel.org, xen-devel@...ts.xenproject.org,
	boris.ostrovsky@...cle.com, david.vrabel@...rix.com,
	mingo@...hat.com, peterz@...radead.org, Douglas_Warzecha@...l.com,
	jdelvare@...e.com, tglx@...utronix.de, hpa@...or.com,
	jeremy@...p.org, chrisw@...s-sol.org, akataria@...are.com,
	rusty@...tcorp.com.au, virtualization@...ts.linux-foundation.org,
	x86@...nel.org
Subject: Re: [PATCH v4 6/6] hwmon: use smp_call_on_cpu() for dell-smm i8k

On 21/04/16 12:57, Pali Rohár wrote:
> On Tuesday 05 April 2016 21:31:52 Pali Rohár wrote:
>> On Tuesday 05 April 2016 16:54:14 Guenter Roeck wrote:
>>> On Tue, Apr 05, 2016 at 07:10:07AM +0200, Juergen Gross wrote:
>>>> Use the smp_call_on_cpu() function to call system management
>>>> mode on cpu 0.
>>>> Make call secure by adding get_online_cpus() to avoid e.g. suspend
>>>> resume cycles in between.
>>>>
>>>> Signed-off-by: Juergen Gross <jgross@...e.com>
>>>> ---
>>>> V4: add call to get_online_cpus()
>>>
>>> Pali, any chance to test this ?
>>
>> I can test it, but just on machine where (probably) smm calls can be 
>> send from any cpu... Need some time for testing and I believe I can do 
>> that at the end of the week.
> 
> Sorry I had absolutely no more free time last weekend :-( And same
> prediction is for this weekend and also next one...

Pali, I've got a Dell laptop (Latitude E6440) here. Would this device be
okay for a test? What would you do for testing? In case you can give me
some hints how to do a sensible test I'd do it.

I've verified by adding a printk() to smp_call_on_cpu() that at least
one of the modified drivers has been used during system boot.


Juergen