From: sashiko-bot@kernel.org
To: "Stefan Roese" <stefan.roese@mailbox.org>
Cc: linux-pci@vger.kernel.org
Subject: Re: [PATCH v2 1/2] PCI/ASPM: Clear ASPM Control on links without common ASPM support
Date: Fri, 02 Oct 2026 09:21:42 +0000 [thread overview]
Message-ID: <20261002092142.D05541F000FF@smtp.kernel.org> (raw)
In-Reply-To: <20261002091029.2225203-2-stefan.roese@mailbox.org>
> pcie_aspm_cap_init() returns early when the two ends of a link share
> no ASPM state. It then never touches Link Control, so ASPM Control
> keeps whatever the device came out of reset with. Per PCIe r7.0, sec
> 5.4.1.4, the result is undefined when L0s or L1 is enabled although
> the other end of the link does not support it.
>
> The Renesas uPD720201 xHCI (1912:0014) resets with LnkCtl 0x0003 (L0s
> and L1 enabled), as the Mini Card CEM and M.2 specs ask for. Behind the
> CPM Root Port of AMD Versal, which supports no ASPM, it only works
> because the chip clears ASPM Control itself during the firmware
> download by xhci-pci-renesas. Once the host has written Link Control,
> even with the unchanged value, it no longer does so. Since commit
> 1a6845aaa6de ("PCI: Initialize RCB from pci_configure_device()")
> pci_configure_rcb() does such a write for every endpoint, ASPM stays
> enabled, and the first access to the xHCI BAR runs into completion
> [ ... ]
>
> Fixes: 1a6845aaa6de ("PCI: Initialize RCB from pci_configure_device()")
> Cc: stable@vger.kernel.org
> Assisted-by: Claude:claude-opus-5-5
> Signed-off-by: Stefan Roese <stefan.roese@mailbox.org>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20261002091029.2225203-1-stefan.roese@mailbox.org?part=1
next prev parent reply other threads:[~2026-10-02 9:21 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-02 9:10 [PATCH v2 0/2] PCI: Fix Renesas uPD720201 hang after the RCB Link Control write Stefan Roese
2026-10-02 9:10 ` [PATCH v2 1/2] PCI/ASPM: Clear ASPM Control on links without common ASPM support Stefan Roese
2026-10-02 9:21 ` sashiko-bot [this message]
2026-10-02 9:10 ` [PATCH v2 2/2] PCI: Set RCB only when the Root Port has it set Stefan Roese
2026-10-02 9:18 ` sashiko-bot
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