Linux PCI subsystem development
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From: Aoxtj <aoxiangtianji@axtjblog.cc>
To: Andreas Wild <andiwild@gmail.com>, Aoxtj <aoxtj@axtjblog.cc>
Cc: linux-pci@vger.kernel.org, Bjorn Helgaas <bhelgaas@google.com>,
	"Maciej W. Rozycki" <macro@orcam.me.uk>,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3] PCI: Skip Target Speed quirk on clamped ports with no link
Date: Tue, 11 Aug 2026 11:43:24 +0800	[thread overview]
Message-ID: <ae819bec-9c2b-47b5-be5e-3c65fea12da1@axtjblog.cc> (raw)
In-Reply-To: <20260808063103.10940-1-andiwild@gmail.com>


On 2026/8/8 14:31, Andreas Wild wrote:
> Expected output:
>
> - "diag: pre" gives the error the retrain returned and whether the
>    link was already down at that point.
> - "diag: post DLLLA=1 after <n>ms" would mean the link does come back,
>    just not before pci_device_add() returns and the bus below is
>    scanned.  That would point at the error path needing to wait for
>    DLLLA rather than only for the Link Training bit to clear.
> - "diag: post DLLLA=0 after 1000ms" would mean the link is genuinely
>    down and staying down, which is a different problem and
>    probably a worse one.
>
> One caveat: the poll loop waits up to a second in the error path, so it
> changes timing.  If the diagnostic build happens to boot reliably where
> the plain v3 build did not, that is also worth reporting.
Diagnostic result: link is genuinely down, not recovering.

Tested 7.0.14-8-pve++ (v3 patch + diagnostic patch) on the same machine. 
Boot fails: SK hynix never enumerates on bus 07.

[0.542354] pci 0000:00:02.4: removing 2.5GT/s downstream link speed 
restriction
[1.623696] pci 0000:00:02.4: retraining failed
[1.623701] diag: pre  ret=-110 DLLLA=0 sta=0x9023 ctl2=0x0023
[3.734697] diag: post DLLLA=0 after 1010ms sta=0x9823
[3.734702] diag: post ctl2=0x0021

Sorry for taking so long to reply; I've been a little busy this week. 
Happy to test anything else.

  reply	other threads:[~2026-08-11  3:43 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-01 20:11 [PATCH v3] PCI: Skip Target Speed quirk on clamped ports with no link Andreas Wild
2026-08-01 20:20 ` sashiko-bot
2026-08-03  5:39 ` Thorsten Leemhuis
2026-08-03 22:07   ` Maciej W. Rozycki
2026-08-04  5:32     ` Thorsten Leemhuis
2026-08-07 19:59 ` Aoxtj
2026-08-08  6:31   ` Andreas Wild
2026-08-11  3:43     ` Aoxtj [this message]
2026-08-11  6:42       ` Andreas Wild

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