linux-kernel - Re: [PATCH v7 5/5] PCI/AER: Only clear error bits in pcie_clear_device

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Message-ID: <aceba0b1-b198-492d-b8c2-073a2b933b18@linux.alibaba.com>
Date: Fri, 6 Feb 2026 15:39:29 +0800
From: Shuai Xue <xueshuai@...ux.alibaba.com>
To: Lukas Wunner <lukas@...ner.de>
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 v7 5/5] PCI/AER: Only clear error bits in
 pcie_clear_device_status()



On 2/3/26 3:53 PM, Lukas Wunner wrote:
> On Sat, Jan 24, 2026 at 03:45:57PM +0800, Shuai Xue wrote:
>> +++ b/drivers/pci/pci.c
>> @@ -2246,7 +2246,7 @@ void pcie_clear_device_status(struct pci_dev *dev)
>>   	u16 sta;
>>   
>>   	pcie_capability_read_word(dev, PCI_EXP_DEVSTA, &sta);
>> -	pcie_capability_write_word(dev, PCI_EXP_DEVSTA, sta);
>> +	pcie_capability_write_word(dev, PCI_EXP_DEVSTA, sta & PCI_EXP_DEVSTA_ERR);
>>   }
> 
> I don't think there's any harm to write error bits which are currently 0,
> so I'd just get rid of the pcie_capability_read_word() and directly write
> the error bits.

Good point. I will remove the read step.

> 
>> +++ b/include/uapi/linux/pci_regs.h
>> @@ -534,6 +534,7 @@
>>   #define  PCI_EXP_DEVSTA_NFED	0x0002	/* Non-Fatal Error Detected */
>>   #define  PCI_EXP_DEVSTA_FED	0x0004	/* Fatal Error Detected */
>>   #define  PCI_EXP_DEVSTA_URD	0x0008	/* Unsupported Request Detected */
>> +#define  PCI_EXP_DEVSTA_ERR	0xf	/* Error bits */
> 
> There's only one user of PCI_EXP_DEVSTA_ERR and it feels a little
> awkward to define a macro in a uapi header which does not correspond
> to an "official" bit definition but is just there for convenience.
> 
> So maybe it's better to simply use the macros for the four bits in
> pcie_clear_device_status()?  Might also be slightly clearer.

Agreed, will move PCI_EXP_DEVSTA_ERR to drivers/pci/pci.c.

> 
> This patch could be submitted individually instead of being part
> of this series.


Got it. Will send a individual patch.

> 
> Thanks,
> 
> Lukas

Thanks for valuable comments.
Shuai