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From: Clemens Ladisch <clemens@ladisch.de>
To: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>,
	Guenter Roeck <linux@roeck-us.net>
Cc: Borislav Petkov <bp@alien8.de>,
	jdelvare@suse.de, rdunlap@infradead.org, bhelgaas@google.com,
	lm-sensors@lm-sensors.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [PATCH] hwmon, k10temp: Add support for AMD F15h M60h processor
Date: Thu, 17 Jul 2014 18:02:17 +0200	[thread overview]
Message-ID: <53C7F389.7010007@ladisch.de> (raw)
In-Reply-To: <53C7EA41.8030907@amd.com>

Aravind Gopalakrishnan wrote:
> On 7/15/2014 4:03 AM, Guenter Roeck wrote:
>> On 07/15/2014 12:41 AM, Clemens Ladisch wrote:
>>> Guenter Roeck wrote:
>>>> On Mon, Jul 14, 2014 at 10:21:51PM +0200, Clemens Ladisch wrote:
>>>>> Borislav Petkov wrote:
>>>>>> On Mon, Jul 14, 2014 at 03:23:08PM -0500, Aravind Gopalakrishnan wrote:
>>>>>>> +    if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model == 0x60) {
>>>>>>> +        pci_bus_write_config_dword(pdev->bus, PCI_DEVFN(0, 0),
>>>>>>> +                       NB_SMU_IND_ADDR, IND_ADDR_OFFSET);
>>>>>>> +        pci_bus_read_config_dword(pdev->bus, PCI_DEVFN(0, 0),
>>>>>>> +                      NB_SMU_IND_DATA, &regval);
>>>>>
>>>>> How do you prevent races with any other code that accesses some indirect
>>>>> register?
>>>
>>> If there actually is any other code; these indirect SMU registers appear
>>> to be mostly undocumented and to be intended to be used by the BIOS.
>>> (Which makes me wonder why the temperature sensor was moved there.)
>>
>> Scary. Does that mean there is a chance they may get used through ACPI ?
>
> I have been asking internally about this, and looks like it's just a register address change.
> So we probably don't have to worry about this being used elsewhere..

The conflict is about the SMU index register; the question is whether
_any_ of these SMU registers is used elsewhere (in a way that could
happen concurrently).


Regards,
Clemens

WARNING: multiple messages have this Message-ID (diff)
From: Clemens Ladisch <clemens@ladisch.de>
To: Aravind Gopalakrishnan <aravind.gopalakrishnan@amd.com>,
	Guenter Roeck <linux@roeck-us.net>
Cc: Borislav Petkov <bp@alien8.de>,
	jdelvare@suse.de, rdunlap@infradead.org, bhelgaas@google.com,
	lm-sensors@lm-sensors.org, linux-doc@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org
Subject: Re: [lm-sensors] [PATCH] hwmon, k10temp: Add support for AMD F15h M60h processor
Date: Thu, 17 Jul 2014 16:02:17 +0000	[thread overview]
Message-ID: <53C7F389.7010007@ladisch.de> (raw)
In-Reply-To: <53C7EA41.8030907@amd.com>

Aravind Gopalakrishnan wrote:
> On 7/15/2014 4:03 AM, Guenter Roeck wrote:
>> On 07/15/2014 12:41 AM, Clemens Ladisch wrote:
>>> Guenter Roeck wrote:
>>>> On Mon, Jul 14, 2014 at 10:21:51PM +0200, Clemens Ladisch wrote:
>>>>> Borislav Petkov wrote:
>>>>>> On Mon, Jul 14, 2014 at 03:23:08PM -0500, Aravind Gopalakrishnan wrote:
>>>>>>> +    if (boot_cpu_data.x86 = 0x15 && boot_cpu_data.x86_model = 0x60) {
>>>>>>> +        pci_bus_write_config_dword(pdev->bus, PCI_DEVFN(0, 0),
>>>>>>> +                       NB_SMU_IND_ADDR, IND_ADDR_OFFSET);
>>>>>>> +        pci_bus_read_config_dword(pdev->bus, PCI_DEVFN(0, 0),
>>>>>>> +                      NB_SMU_IND_DATA, &regval);
>>>>>
>>>>> How do you prevent races with any other code that accesses some indirect
>>>>> register?
>>>
>>> If there actually is any other code; these indirect SMU registers appear
>>> to be mostly undocumented and to be intended to be used by the BIOS.
>>> (Which makes me wonder why the temperature sensor was moved there.)
>>
>> Scary. Does that mean there is a chance they may get used through ACPI ?
>
> I have been asking internally about this, and looks like it's just a register address change.
> So we probably don't have to worry about this being used elsewhere..

The conflict is about the SMU index register; the question is whether
_any_ of these SMU registers is used elsewhere (in a way that could
happen concurrently).


Regards,
Clemens

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lm-sensors@lm-sensors.org
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  reply	other threads:[~2014-07-17 16:02 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-07-14 20:23 [PATCH] hwmon, k10temp: Add support for AMD F15h M60h processor Aravind Gopalakrishnan
2014-07-14 20:23 ` [lm-sensors] " Aravind Gopalakrishnan
2014-07-14 19:51 ` Borislav Petkov
2014-07-14 19:51   ` [lm-sensors] " Borislav Petkov
2014-07-14 19:59   ` Aravind Gopalakrishnan
2014-07-14 19:59     ` [lm-sensors] " Aravind Gopalakrishnan
2014-07-14 20:06     ` Guenter Roeck
2014-07-14 20:06       ` [lm-sensors] " Guenter Roeck
2014-07-14 20:21   ` Clemens Ladisch
2014-07-14 20:21     ` [lm-sensors] " Clemens Ladisch
2014-07-14 20:33     ` Guenter Roeck
2014-07-14 20:33       ` [lm-sensors] " Guenter Roeck
2014-07-15  7:41       ` Clemens Ladisch
2014-07-15  7:41         ` [lm-sensors] " Clemens Ladisch
2014-07-15  9:03         ` Guenter Roeck
2014-07-15  9:03           ` [lm-sensors] " Guenter Roeck
2014-07-17 15:22           ` Aravind Gopalakrishnan
2014-07-17 15:22             ` [lm-sensors] " Aravind Gopalakrishnan
2014-07-17 16:02             ` Clemens Ladisch [this message]
2014-07-17 16:02               ` Clemens Ladisch
  -- strict thread matches above, loose matches on Subject: below --
2014-03-11 21:25 [lm-sensors] [PATCH] hwmon, k10temp: Add support for AMD F16 M30h processor Aravind Gopalakrishnan
2014-03-11 21:25 ` Aravind Gopalakrishnan
2014-03-12  3:06 ` [lm-sensors] " Guenter Roeck
2014-03-12  3:06   ` Guenter Roeck
2014-03-12  9:25   ` [lm-sensors] " Jean Delvare
2014-03-12  9:25     ` Jean Delvare
2014-03-12 14:34     ` [lm-sensors] " Aravind Gopalakrishnan
2014-03-12 14:34       ` Aravind Gopalakrishnan

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