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Date: Tue, 5 May 2026 11:05:25 -0500
From: Bjorn Helgaas <helgaas@kernel.org>
To: Mario Limonciello <mario.limonciello@amd.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
	"open list:PCI SUBSYSTEM" <linux-pci@vger.kernel.org>,
	open list <linux-kernel@vger.kernel.org>,
	"Rafael J . Wysocki" <rafael@kernel.org>,
	Lukas Wunner <lukas@wunner.de>, linux-pm@vger.kernel.org
Subject: Re: [PATCH] PCI/ASPM: Enable L0s/L1 for removable devices when BIOS
 didn't configure ASPM
Message-ID: <20260505160525.GA733339@bhelgaas>
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In-Reply-To: <20260504225246.480921-1-mario.limonciello@amd.com>

On Mon, May 04, 2026 at 05:52:46PM -0500, Mario Limonciello wrote:
> When comparing lspci output between Windows and Linux for hotplugged
> Thunderbolt 5 eGPU devices, Windows enables ASPM L1 but Linux doesn't:
> 
>   Windows: LnkCtl: ASPM L1 Enabled
>   Linux:   LnkCtl: ASPM Disabled
> 
> This difference in ASPM configuration can cause behavioral differences
> between the two operating systems for the same hardware.

A tangent, not a comment on the patch itself, but what sort of
behavioral differences are these?  If ASPM is working correctly, the
only differences *should* be in power consumption and performance.