From: sashiko-bot@kernel.org
To: "Gowtham Kudupudi" <gowtham@ferryfair.com>
Cc: neil.armstrong@linaro.org, linux-amlogic@lists.infradead.org,
linux-pci@vger.kernel.org
Subject: Re: [PATCH] PCI: meson: Fix PERST# timing by asserting reset before LTSSM enable
Date: Sun, 14 Jun 2026 02:31:39 +0000 [thread overview]
Message-ID: <20260614023139.A51F41F000E9@smtp.kernel.org> (raw)
In-Reply-To: <20260614015620.20432-1-gowtham@ferryfair.com>
> On warm reboot, the PCIe controller's LTSSM starts link training
> immediately if PERST# is already deasserted from the previous boot.
> The driver then pulses PERST# for only 500us, which is too short to
> properly reset the endpoint device that has already started training.
>
> Fix by moving the PERST# assert/deassert pulse BEFORE enabling LTSSM,
> so the endpoint gets a clean reset cycle before link training begins.
>
> This was found on Amlogic G12B (A311D) with NVMe on an M.2 slot.
> Cold boot worked because POR held PERST# low; warm reboot did not.
> The fix was confirmed on a Banana Pi CM4 with Waveshare IO base board.
>
> Signed-off-by: Gowtham Kudupudi <gowtham@ferryfair.com>
Sashiko has reviewed this patch and found no issues. It looks great!
--
Sashiko AI review · https://sashiko.dev/#/patchset/20260614015620.20432-1-gowtham@ferryfair.com?part=1
next parent reply other threads:[~2026-06-14 2:31 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20260614015620.20432-1-gowtham@ferryfair.com>
2026-06-14 2:31 ` sashiko-bot [this message]
2026-06-15 10:34 ` [PATCH] PCI: meson: Fix PERST# timing by asserting reset before LTSSM enable Ronald Claveau
2026-06-16 6:06 ` neil.armstrong
2026-06-16 23:36 ` gowtham
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260614023139.A51F41F000E9@smtp.kernel.org \
--to=sashiko-bot@kernel.org \
--cc=gowtham@ferryfair.com \
--cc=linux-amlogic@lists.infradead.org \
--cc=linux-pci@vger.kernel.org \
--cc=neil.armstrong@linaro.org \
--cc=sashiko-reviews@lists.linux.dev \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox