linux-kernel - Re: [RFC] hwmon: (fam15h_power) Add bit masking for tdp

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Date:	Wed, 27 Jan 2016 11:36:33 +0100
From:	Gi-Oh Kim <gi-oh.kim@...fitbricks.com>
To:	Huang Rui <ray.huang@....com>
Cc:	Guenter Roeck <linux@...ck-us.net>,
	"lm-sensors@...sensors.org" <lm-sensors@...sensors.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Borislav Petkov <bp@...en8.de>
Subject: Re: [RFC] hwmon: (fam15h_power) Add bit masking for tdp_limit



On 27.01.2016 07:45, Huang Rui wrote:
> On Tue, Jan 26, 2016 at 11:57:35AM +0100, Gi-Oh Kim wrote:
>>
>> On 26.01.2016 03:25, Huang Rui wrote:
>>> On Mon, Jan 25, 2016 at 07:41:07PM +0800, Gioh Kim wrote:
>> Thanks for your reply.
>> I'm not completely sure that the reserved bits are always zero.
>> Are they always zero?
>> Or do we need bit-masking like following?
>>
> Reserved bits aren't always zero. But here they are reserved for
> ApmTdpLimit expansion.
>
> Yes, we would better add bit-masking here. :-)
>
>> -------------- 8< -----------------
>> Subject: [PATCH] hwmon: (fam15h_power) Add bit masking for tdp_limit
>>
>> Add bit masking to read ApmTdpLimit precisely
>>
>> Signed-off-by: Gioh Kim <gi-oh.kim@...fitbricks.com>
>> ---
>>   drivers/hwmon/fam15h_power.c | 6 +++++-
>>   1 file changed, 5 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/hwmon/fam15h_power.c b/drivers/hwmon/fam15h_power.c
>> index f77eb97..edbcf6c 100644
>> --- a/drivers/hwmon/fam15h_power.c
>> +++ b/drivers/hwmon/fam15h_power.c
>> @@ -90,7 +90,11 @@ static ssize_t show_power(struct device *dev,
>>       pci_bus_read_config_dword(f4->bus, PCI_DEVFN(PCI_SLOT(f4->devfn), 5),
>>                     REG_TDP_LIMIT3, &val);
>>
>> -    tdp_limit = val >> 16;
>> +    if (boot_cpu_data.x86_model >= 0x60)
>> +        tdp_limit = val >> 16;
> You need add CPU family check and a comment to mention bit field
> change. This updates since family 15h and model 60h.
>
> if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model >= 0x60)

I'm going to send a formal patch.
Thank you.

>
> Thanks,
> Rui

-- 
Best regards,
Gi-Oh Kim