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From: "Krzysztof Wilczyński" <kw@linux.com>
To: Hongxing Zhu <hongxing.zhu@nxp.com>
Cc: Bjorn Helgaas <helgaas@kernel.org>,
	"bhelgaas@google.com" <bhelgaas@google.com>,
	"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
	Frank Li <frank.li@nxp.com>, "mani@kernel.org" <mani@kernel.org>,
	"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
	"linux-arm-kernel@lists.infradead.org"
	<linux-arm-kernel@lists.infradead.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"kernel@pengutronix.de" <kernel@pengutronix.de>,
	"imx@lists.linux.dev" <imx@lists.linux.dev>
Subject: Re: [PATCH v2] PCI: dwc: Fix resume failure if no EP is connected at some platforms
Date: Thu, 7 Nov 2024 16:20:05 +0900	[thread overview]
Message-ID: <20241107072005.GA378841@rocinante> (raw)
In-Reply-To: <AS8PR04MB8676C98C4001DDC4851035B18C5C2@AS8PR04MB8676.eurprd04.prod.outlook.com>

Hello,

> > But I don't think you responded to the race question.  What happens here?
> > 
> >   if (dw_pcie_get_ltssm(pci) > DW_PCIE_LTSSM_DETECT_ACT) {
> >     --> link goes down here <--
> >     pci->pp.ops->pme_turn_off(&pci->pp);
> > 
> > You decide the LTSSM is active and the link is up.  Then the link goes down.
> > Then you send PME_Turn_off.  Now what?
> > 
> > If it's safe to try to send PME_Turn_off regardless of whether the link is up or
> > down, there would be no need to test the LTSSM state.
> I made a local tests on i.MX95/i.MX8QM/i.MX8MP/i.MX8MM/i.MX8MQ, and
> confirm that it's safe to send PME_TURN_OFF although the link is down.
> You're right. It's no need to test LTSSM state here.
> So do the L2 poll listed above after PME_TURN_OFF is sent.
> 
> Since the 6.13 merge window is almost closed.
> How about I prepare another Fix patch to do the following items for incoming
> 6.14?
> - Before sending PME_TURN_OFF, don't test the LTSSM stat.
> - Remove the L2 stat poll, after sending PME_TURN_OFF.

If the changes aren't too involved, then I would rather fix it or drop the
not needed code now, before we sent the Pull Request.

So, feel free to sent a small patch against the current branch, or simply
let me know how do you wish the current code to be changed, so I can do it
against the current branch.

Thank you!

	Krzysztof


  reply	other threads:[~2024-11-07  8:46 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-07-22  6:15 [PATCH v2] PCI: dwc: Fix resume failure if no EP is connected at some platforms Richard Zhu
2024-11-03 20:56 ` Krzysztof Wilczyński
2024-11-06  6:18   ` Hongxing Zhu
2024-11-06 15:07     ` Krzysztof Wilczy��ski
2024-11-07  1:51       ` Hongxing Zhu
2024-11-05 23:27 ` Bjorn Helgaas
2024-11-06  1:59   ` Hongxing Zhu
2024-11-06 22:29     ` Bjorn Helgaas
2024-11-07  6:16       ` Hongxing Zhu
2024-11-07  7:20         ` Krzysztof Wilczyński [this message]
2024-11-07  8:40           ` Hongxing Zhu
2024-11-07  8:47             ` Hongxing Zhu
2024-11-07 16:30               ` Krzysztof Wilczy��ski
2024-11-07 16:57                 ` Frank Li
2024-11-07 19:16                   ` Krzysztof Wilczy��ski
2024-11-05 23:35 ` Bjorn Helgaas
2024-11-06  2:06   ` Hongxing Zhu

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