From: Bjorn Helgaas <helgaas@kernel.org>
To: Richard Cheng <icheng@nvidia.com>
Cc: bhelgaas@google.com, linux-pci@vger.kernel.org,
linux-kernel@vger.kernel.org, jan@nvidia.com, newtonl@nvidia.com,
sreddym@nvidia.com, skomatineni@nvidia.com, vidyas@nvidia.com,
kristinc@nvidia.com, kaihengf@nvidia.com, mochs@nvidia.com
Subject: Re: [PATCH] PCI/NPEM: Set LED_HW_PLUGGABLE for hotplug-capable ports
Date: Mon, 6 Apr 2026 12:35:49 -0500 [thread overview]
Message-ID: <20260406173549.GA171987@bhelgaas> (raw)
In-Reply-To: <20260402093850.23075-1-icheng@nvidia.com>
On Thu, Apr 02, 2026 at 05:38:50PM +0800, Richard Cheng wrote:
> NPEM registers LED classdevs on PCI endpoint that may be behind
> hotplug-capable ports. During hot-removal, led_classdev_unregister()
> calls led_set_brightness(LED_OFF) which PCI config on a disconnected
> device, returning -ENODEV:
>
> ```
> leds 0003:01:00.0:enclosure:ok: Setting an LED's brightness failed (-19)
> ```
>
> The LED core already suppresses this for devices with LED_HW_PLUGGABLE
> set, but NPEM never sets it. Add the flag since NPEM LEDs are on
> hot-pluggable hardware by nature.
>
> Fixes: 4e893545ef87 ("PCI/NPEM: Add Native PCIe Enclosure Management support")
> Signed-off-by: Richard Cheng <icheng@nvidia.com>
> Acked-by: Kai-Heng Feng <kaihengf@nvidia.com>
Applied to pci/hotplug for v7.1, thank you!
> ---
> The bug was triggered on an ARM64 machine with CPU model Olympus.
> Kernel version is v6.17.
> The PCI topology is
> ```
> $ sudo lspci -tv
> -[0001:00]---00.0-[01]--+-00.0 Mellanox Technologies CX8 Family [ConnectX-8]
> +-00.1 Mellanox Technologies CX8 Family [ConnectX-8]
> +-00.2 Mellanox Technologies CX8 Family [ConnectX-8]
> \-00.3 Mellanox Technologies CX8 Family [ConnectX-8]
> -[0002:00]---00.0-[01]--
> -+-[0003:00]---00.0-[01]----00.0 Montage Technology Co., Ltd. Device c002
> \-[0003:80]---00.0-[81]----00.0 Montage Technology Co., Ltd. Device c002
> -[0004:00]---00.0-[01]--
> -+-[0005:00]---00.0-[01]----00.0 Samsung Electronics Co Ltd Device a810
> +-[0005:40]---00.0-[41]----00.0 Samsung Electronics Co Ltd Device a810
> +-[0005:c0]---00.0-[c1]----00.0 Intel Corporation I210 Gigabit Network Connection
> \-[0005:e0]---00.0-[e1-e2]----00.0-[e2]--+-00.0 ASPEED Technology, Inc. ASPEED Graphics Family
> \-02.0 ASPEED Technology, Inc. Device 2603
> -+-[0006:00]---00.0-[01]--
> \-[0006:80]---00.0-[81]--
> ```
> We're targeting on 0003:01:00.0 CXL [0502]: Montage Technology Co., Ltd. Device [1b00:c002] (rev 03).
> First use `sudo setpci -s 0003:00:00.0 0x1f4.w=0x0002` to set UnmaskLinkDisable in CXL DVSEC.
> Then disable the link with `sudo setpci -v -s 0003:00:00.0 CAP_EXP+0x10.b=0x10:0x10`
>
>
> Best regards,
> Richard Cheng.
> ---
> drivers/pci/npem.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/pci/npem.c b/drivers/pci/npem.c
> index ffeeedf6e311..c51879fcd438 100644
> --- a/drivers/pci/npem.c
> +++ b/drivers/pci/npem.c
> @@ -504,7 +504,7 @@ static int pci_npem_set_led_classdev(struct npem *npem, struct npem_led *nled)
> led->brightness_get = brightness_get;
> led->max_brightness = 1;
> led->default_trigger = "none";
> - led->flags = 0;
> + led->flags = LED_HW_PLUGGABLE;
>
> ret = led_classdev_register(&npem->dev->dev, led);
> if (ret)
> --
> 2.43.0
>
prev parent reply other threads:[~2026-04-06 17:35 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-02 9:38 [PATCH] PCI/NPEM: Set LED_HW_PLUGGABLE for hotplug-capable ports Richard Cheng
2026-04-05 7:41 ` Lukas Wunner
2026-04-06 17:35 ` Bjorn Helgaas [this message]
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=20260406173549.GA171987@bhelgaas \
--to=helgaas@kernel.org \
--cc=bhelgaas@google.com \
--cc=icheng@nvidia.com \
--cc=jan@nvidia.com \
--cc=kaihengf@nvidia.com \
--cc=kristinc@nvidia.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=mochs@nvidia.com \
--cc=newtonl@nvidia.com \
--cc=skomatineni@nvidia.com \
--cc=sreddym@nvidia.com \
--cc=vidyas@nvidia.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.