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From: Niklas Schnelle <niks@kernel.org>
To: Lukas Wunner <lukas@wunner.de>, Bjorn Helgaas <helgaas@kernel.org>
Cc: linux-pci@vger.kernel.org,
	Ilpo Jarvinen <ilpo.jarvinen@linux.intel.com>,
	 Jonathan Cameron <Jonathan.Cameron@huawei.com>,
	Mika Westerberg <mika.westerberg@linux.intel.com>,
	"Maciej W. Rozycki" <macro@orcam.me.uk>,
	Mario Limonciello <mario.limonciello@amd.com>
Subject: Re: [PATCH for-linus v2 2/3] PCI: Honor Max Link Speed when determining supported speeds
Date: Sun, 15 Dec 2024 21:56:08 +0100	[thread overview]
Message-ID: <d29a11adc3c9a249f774547b430fd9b2d4e7b555.camel@kernel.org> (raw)
In-Reply-To: <0044d6cd05ad20ec3a6ec5a8a22b6ab652e251fe.1734257330.git.lukas@wunner.de>

On Sun, 2024-12-15 at 11:20 +0100, Lukas Wunner wrote:
> The Supported Link Speeds Vector in the Link Capabilities 2 Register
> indicates the *supported* link speeds.  The Max Link Speed field in
> the Link Capabilities Register indicates the *maximum* of those speeds.
> 
> pcie_get_supported_speeds() neglects to honor the Max Link Speed field
> and will thus incorrectly deem higher speeds as supported.  Fix it.
> 
> One user-visible issue addressed here is an incorrect value in the sysfs
> attribute "max_link_speed".

Can confirm that I saw this effect on my affected Intel JHL7540 "Titan
Ridge 2018" Thunderbolt controller.

Feel free to add:

Tested-by: Niklas Schnelle <niks@kernel.org>


  reply	other threads:[~2024-12-15 20:56 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-12-15 10:20 [PATCH for-linus v2 0/3] Fix bwctrl boot hang Lukas Wunner
2024-12-15 10:20 ` [PATCH for-linus v2 1/3] PCI: Assume 2.5 GT/s if Max Link Speed is undefined Lukas Wunner
2024-12-15 21:17   ` Niklas Schnelle
2024-12-16  6:45     ` Lukas Wunner
2024-12-16 10:51   ` Jonathan Cameron
2024-12-16 14:09   ` Ilpo Järvinen
2024-12-16 14:17   ` Mario Limonciello
2024-12-15 10:20 ` [PATCH for-linus v2 2/3] PCI: Honor Max Link Speed when determining supported speeds Lukas Wunner
2024-12-15 20:56   ` Niklas Schnelle [this message]
2024-12-16 10:53   ` Jonathan Cameron
2024-12-16 14:12   ` Ilpo Järvinen
2024-12-15 10:20 ` [PATCH for-linus v2 3/3] PCI/bwctrl: Enable only if more than one speed is supported Lukas Wunner
2024-12-15 21:03   ` Niklas Schnelle
2024-12-16 11:32   ` Jonathan Cameron
2024-12-16 14:20     ` Mario Limonciello

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