linux-kernel - Re: [PATCH v6 4/5] PCI/ERR: Use pcie_aer_is_native() to check for native AER control

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Message-ID: <aPrvEZ3X4_tiD2Fh@wunner.de>
Date: Fri, 24 Oct 2025 05:14:25 +0200
From: Lukas Wunner <lukas@...ner.de>
To: Shuai Xue <xueshuai@...ux.alibaba.com>
Cc: Bjorn Helgaas <bhelgaas@...gle.com>, linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
	kbusch@...nel.org, sathyanarayanan.kuppuswamy@...ux.intel.com,
	mahesh@...ux.ibm.com, oohall@...il.com, Jonathan.Cameron@...wei.com,
	terry.bowman@....com, tianruidong@...ux.alibaba.com
Subject: Re: [PATCH v6 4/5] PCI/ERR: Use pcie_aer_is_native() to check for
 native AER control

On Fri, Oct 24, 2025 at 11:09:25AM +0800, Shuai Xue wrote:
> 2025/10/23 18:29, Lukas Wunner:
> > On Mon, Oct 20, 2025 at 10:45:31PM +0800, Shuai Xue wrote:
> > > From PCIe spec, BIT 0-2 are logged for functions supporting Advanced
> > > Error Handling.
> > > 
> > > I am not sure if we should clear BIT 3, and also BIT 6 (Emergency Power
> > > Reduction Detected) and in case a AER error.
> > 
> > AFAIUI, bits 0 to 3 are what the PCIe r7.0 sec 6.2.1 calls
> > "baseline capability" error reporting.  They're supported
> > even if AER is not supported.
> > 
> > Bit 6 has nothing to do with this AFAICS.
> 
> Per PCIe r7.0 section 7.5.3.5:
> 
>   **For Functions supporting Advanced Error Handling**, errors are logged
>   in this register regardless of the settings of the Uncorrectable Error
>   Mask register. Default value of this bit is 0b.
> 
> From this, it's clear that bits 0 to 2 are not logged unless AER is supported.

No.  It just means that if AER is supported, the Uncorrectable Error Mask
register has no bearing on whether the bits in the Device Status register
are set.  It does not mean that the bits are only set if AER is supported.

Thanks,

Lukas