Re: [PATCH 0/6] PCI: dwc: Revert Link Up IRQ support

From: Niklas Cassel <cassel@kernel.org>
To: Manivannan Sadhasivam <mani@kernel.org>
Cc: "Jingoo Han" <jingoohan1@gmail.com>,
	"Lorenzo Pieralisi" <lpieralisi@kernel.org>,
	"Krzysztof Wilczyński" <kwilczynski@kernel.org>,
	"Rob Herring" <robh@kernel.org>,
	"Bjorn Helgaas" <bhelgaas@google.com>,
	"Heiko Stuebner" <heiko@sntech.de>,
	"Shawn Lin" <shawn.lin@rock-chips.com>,
	"FUKAUMI Naoki" <naoki@radxa.com>,
	"Krishna chaitanya chundru" <quic_krichai@quicinc.com>,
	linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org,
	linux-arm-msm@vger.kernel.org
Subject: Re: [PATCH 0/6] PCI: dwc: Revert Link Up IRQ support
Date: Mon, 24 Nov 2025 15:02:51 +0100	[thread overview]
Message-ID: <aSRli_Mb6qoQ9TZO@ryzen> (raw)
In-Reply-To: <mt7miqkipr4dvxemftq6octxqzauueln252ncrcwy6i2t7wfhi@jtwokeilhwsi>

On Mon, Nov 24, 2025 at 06:07:44PM +0530, Manivannan Sadhasivam wrote:
> While I suggested to revert the link up IRQ patch for rockchip earlier, I didn't
> expect to drop the support for Qcom. The reason is, on Qcom SoCs, we have not
> seen a case where people connect a random PCIe switch and saw failures. Most of
> the Qcom usecases were around the M.2 and other proprietary connectors. There is
> only one in-house PCIe switch that is being actively used in our products, but
> so far, none of the bootloaders have turned them ON before kernel booting. So
> kernel relies on the newly merged pwrctrl driver to do the job. Even though it
> also suffers from the same resource allocation issue, this series won't help in
> any way as pwrctrl core performs rescan after the switch power ON, and by that
> time, it will be very late anyway.
> 
> So I'm happy to take the rockhip patches from this series as they fix the real
> issue that people have reported. But once the pwrctrl rework series gets merged,
> and the rockchip drivers support them, we can bring back the reverted changes.

FUKAUMI Naoki, just to confirm:

Neither my suggested approach:
https://lore.kernel.org/linux-pci/aRHdeVCY3rRmxe80@ryzen/

nor Shawn's suggested approach:
https://lore.kernel.org/linux-pci/dc932773-af5b-4af7-a0d0-8cc72dfbd3c7@rock-chips.com/

worked for you?

If so, I don't see many alternative but for Mani to apply patch 1 and
patch 2 from this series.

Kind regards,
Niklas