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: <aPZAAPEGBNk_ec36@wunner.de>
Date: Mon, 20 Oct 2025 15:58:24 +0200
From: Lukas Wunner <lukas@...ner.de>
To: Shuai Xue <xueshuai@...ux.alibaba.com>
Cc: linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	linuxppc-dev@...ts.ozlabs.org, bhelgaas@...gle.com,
	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 Mon, Oct 20, 2025 at 09:09:41PM +0800, Shuai Xue wrote:
> ??? 2025/10/20 18:17, Lukas Wunner ??????:
> > On Wed, Oct 15, 2025 at 10:41:58AM +0800, Shuai Xue wrote:
> > > Replace the manual checks for native AER control with the
> > > pcie_aer_is_native() helper, which provides a more robust way
> > > to determine if we have native control of AER.
> > 
> > Why is it more robust?
> 
> IMHO, the pcie_aer_is_native() helper is more robust because it includes
> additional safety checks that the manual approach lacks:
[...]
> Specifically, it performs a sanity check for dev->aer_cap before
> evaluating native AER control.

I'm under the impression that aer_cap must be set, otherwise the
error wouldn't have been reported and we wouldn't be in this code path?

If we can end up in this code path without aer_cap set, your patch
would regress devices which are not AER-capable because it would
now skip clearing of errors in the Device Status register via
pcie_clear_device_status().

Thanks,

Lukas