linux-kernel - Re: [PATCH v2 1/1] PCI: Update Link Speed after retraining

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Message-ID: <174732656472.65286.1704390633596082407.b4-ty@kernel.org>
Date: Thu, 15 May 2025 16:29:45 +0000
From: Krzysztof Wilczyński <kwilczynski@...nel.org>
To: Lukas Wunner <lukas@...ner.de>,
	Bjorn Helgaas <bhelgaas@...gle.com>,
	linux-pci@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Ilpo Järvinen <ilpo.jarvinen@...ux.intel.com>
Subject: Re: [PATCH v2 1/1] PCI: Update Link Speed after retraining

Hello,

> PCIe Link Retraining can alter Link Speed. pcie_retrain_link() that
> performs the Link Training is called from bwctrl and ASPM driver.
> 
> While bwctrl listens for Link Bandwidth Management Status (LBMS) to
> pick up changes in Link Speed, there is a race between
> pcie_reset_lbms() clearing LBMS after the Link Training and
> pcie_bwnotif_irq() reading the Link Status register. If LBMS is already
> cleared when the irq handler reads the register, the interrupt handler
> will return early with IRQ_NONE and won't update the Link Speed.
> 
> [...]

Applied to bwctrl, thank you!

[1/1] PCI: Update Link Speed after retraining
      https://git.kernel.org/pci/pci/c/6ade6e81f898

	Krzysztof