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From: Sinan Kaya <okaya@kernel.org>
To: "Kuppuswamy,
	Sathyanarayanan"  <sathyanarayanan.kuppuswamy@linux.intel.com>,
	Lukas Wunner <lukas@wunner.de>,
	Sathyanarayanan Kuppuswamy Natarajan 
	<sathyanarayanan.nkuppuswamy@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>,
	Bjorn Helgaas <bhelgaas@google.com>,
	Linux PCI <linux-pci@vger.kernel.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	"Raj, Ashok" <ashok.raj@intel.com>,
	Keith Busch <kbusch@kernel.org>,
	knsathya@kernel.org
Subject: Re: [PATCH v2 1/1] PCI: pciehp: Skip DLLSC handling if DPC is triggered
Date: Thu, 18 Mar 2021 11:35:55 -0400	[thread overview]
Message-ID: <1069dc19-35ac-be1a-b02a-3815503cb295@kernel.org> (raw)
In-Reply-To: <0a020128-80e8-76a7-6b94-e165d3c6f778@linux.intel.com>

On 3/17/2021 4:02 PM, Kuppuswamy, Sathyanarayanan wrote:
> My point is, there is no race in OS handlers (pciehp_ist() vs
> pcie_do_recovery())
>  However, Sinan wrote in
>> 2018 that one of the issues with hotplug versus DPC is that pciehp
>> may turn off slot power and thereby foil DPC recovery.  (Power off =
>> cold reset, whereas DPC recovery = warm reset.)  This can occur
>> as well if DPC is handled by firmware. 

It has been a while...

If I remember correctly, there is no race condition if the platform
handles DPC and HP interrupts on the same MSI vector.

If HP and DPC interrupts are handled as MSI-x interrupts, these can
fire out of order and can cause problems for each one.

I hope it helps.

  reply	other threads:[~2021-03-18 15:37 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-03-13  3:32 [PATCH v2 1/1] PCI: pciehp: Skip DLLSC handling if DPC is triggered sathyanarayanan.kuppuswamy
2021-03-13  3:35 ` Kuppuswamy, Sathyanarayanan
2021-03-17  4:13 ` Lukas Wunner
2021-03-17  5:08   ` Dan Williams
2021-03-17  5:31     ` Lukas Wunner
2021-03-17 16:31       ` Dan Williams
2021-03-17 17:19         ` Sathyanarayanan Kuppuswamy Natarajan
2021-03-17 17:45           ` Dan Williams
2021-03-17 17:54             ` Sathyanarayanan Kuppuswamy Natarajan
2021-03-17 19:01               ` Lukas Wunner
2021-03-17 20:02                 ` Kuppuswamy, Sathyanarayanan
2021-03-18 15:35                   ` Sinan Kaya [this message]
2021-03-28  9:53                   ` Lukas Wunner
2021-03-17 19:09             ` Lukas Wunner
2021-03-17 19:22               ` Raj, Ashok
2021-03-17 19:40                 ` Lukas Wunner
2021-03-28  5:49   ` Kuppuswamy, Sathyanarayanan
2021-03-28  9:07     ` Lukas Wunner

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