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Message-ID: <e17b38fe-97cb-4559-be97-36af0ab14789@amd.com>
Date: Wed, 5 Jun 2024 12:30:35 -0400
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Cc: yazen.ghannam@amd.com, Guenter Roeck <linux@roeck-us.net>,
 x86@kernel.org, Mario Limonciello <mario.limonciello@amd.com>,
 linux-edac@vger.kernel.org, linux-kernel@vger.kernel.org,
 linux-hwmon@vger.kernel.org
Subject: Re: [PATCH v3 3/8] hwmon: (k10temp) Check return value of
 amd_smn_read()
To: Borislav Petkov <bp@alien8.de>
References: <20240523-fix-smn-bad-read-v3-0-aa44c622de39@amd.com>
 <20240523-fix-smn-bad-read-v3-3-aa44c622de39@amd.com>
 <20240605122012.GXZmBX_KFQArXB9Lar@fat_crate.local>
 <7a7c2f41-1608-4348-9183-d99aaa51398e@amd.com>
 <20240605161236.GIZmCOdP-CRPJ8-3sY@fat_crate.local>
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From: Yazen Ghannam <yazen.ghannam@amd.com>
In-Reply-To: <20240605161236.GIZmCOdP-CRPJ8-3sY@fat_crate.local>
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On 6/5/24 12:12 PM, Borislav Petkov wrote:
> On Wed, Jun 05, 2024 at 09:41:51AM -0400, Yazen Ghannam wrote:
>> I agree that patches 1-3 are not stable-worthy on their own. But I think
>> patch 4 is, and it requires 1-3 to avoid build errors.
> 
> Which of the rules in the first section of
> Documentation/process/stable-kernel-rules.rst apply for patch 4?
> 
> Because I don't see it.
>

"It fixes a problem like ... a hardware quirk ..."

This is described in patch 4:
---
Most systems will return 0 for SMN addresses that are not accessible.
This is in line with AMD convention that unavailable registers are
Read-as-Zero/Writes-Ignored.

However, some systems will return a "PCI Error Response" instead. This
value, along with an error code of 0 from the PCI config access, will
confuse callers of the amd_smn_read() function.
---

But I think it's fine to drop the stable tag after reading through the
rules again. I'll do option 2 or 3 if there's interest for specific
branches. And the cherry-pick thing should be easy to do if all the
prerequisites are already upstream.

Thanks,
Yazen