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Message-ID: <ca836507-50ca-13bc-ef88-7f69b1333c99@linux.intel.com>
Date:   Tue, 4 Oct 2022 20:28:07 -0700
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Subject: Re: [PATCH 0/3] PCI/ASPM: Fix L1SS issues
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To:     Bjorn Helgaas <helgaas@kernel.org>, linux-pci@vger.kernel.org
Cc:     Vidya Sagar <vidyas@nvidia.com>,
        "Saheed O . Bolarinwa" <refactormyself@gmail.com>,
        Lorenzo Pieralisi <lpieralisi@kernel.org>,
        =?UTF-8?Q?Krzysztof_Wilczy=c5=84ski?= <kw@linux.com>,
        Rajat Jain <rajatja@google.com>,
        "Kenneth R . Crudup" <kenny@panix.com>,
        Kai-Heng Feng <kai.heng.feng@canonical.com>,
        Abhishek Sahu <abhsahu@nvidia.com>,
        Thierry Reding <treding@nvidia.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Krishna Thota <kthota@nvidia.com>,
        Manikanta Maddireddy <mmaddireddy@nvidia.com>,
        Vidya Sagar <sagar.tv@gmail.com>, sagupta@nvidia.com,
        linux-kernel@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>
References: <20221005025809.2247547-1-helgaas@kernel.org>
From:   Sathyanarayanan Kuppuswamy 
        <sathyanarayanan.kuppuswamy@linux.intel.com>
In-Reply-To: <20221005025809.2247547-1-helgaas@kernel.org>
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On 10/4/22 7:58 PM, Bjorn Helgaas wrote:
> From: Bjorn Helgaas <bhelgaas@google.com>
> 
> This is really late, but I think we have two significant issues with L1SS:
> 
>   1) pcie_aspm_cap_init() reads from the L1SS capability even when it
>   doesn't exist, so it reads PCI_COMMAND and PCI_STATUS instead and treats
>   those as an L1SS Capability value.
> 
>   2) encode_l12_threshold() encodes LTR_L1.2_THRESHOLD as smaller than
>   requested, so ports may enter L1.2 when they should not.
> 
> These patches are intended to fix both issues.

Looks good to me.

Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>

> 
> Bjorn Helgaas (3):
>   PCI/ASPM: Factor out L1 PM Substates configuration
>   PCI/ASPM: Ignore L1 PM Substates if device lacks capability
>   PCI/ASPM: Correct LTR_L1.2_THRESHOLD computation
> 
>  drivers/pci/pcie/aspm.c | 155 +++++++++++++++++++++++-----------------
>  1 file changed, 90 insertions(+), 65 deletions(-)
> 

-- 
Sathyanarayanan Kuppuswamy
Linux Kernel Developer