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From: =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= <ilpo.jarvinen@linux.intel.com>
Date: Tue, 28 May 2024 13:54:01 +0300 (EEST)
To: Bitao Hu <yaoma@linux.alibaba.com>
cc: Lukas Wunner <lukas@wunner.de>, bhelgaas@google.com, 
    weirongguang@kylinos.cn, linux-pci@vger.kernel.org, 
    LKML <linux-kernel@vger.kernel.org>, kanie@linux.alibaba.com
Subject: Re: [PATCHv2] PCI: pciehp: Use appropriate conditions to check the
 hotplug controller status
In-Reply-To: <20240528064200.87762-1-yaoma@linux.alibaba.com>
Message-ID: <d9529e4c-05eb-d6eb-c8b7-248fd21338d1@linux.intel.com>
References: <20240524063023.77148-1-yaoma@linux.alibaba.com> <20240528064200.87762-1-yaoma@linux.alibaba.com>
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On Tue, 28 May 2024, Bitao Hu wrote:

> "present" and "link_active" can be 1 if the status is ready, and 0 if
> it is not. Both of them can be -ENODEV if reading the config space
> of the hotplug port failed. That's typically the case if the hotplug
> port itself was hot-removed. Therefore, this situation can occur:
> pciehp_card_present() may return 1 and pciehp_check_link_active()
> may return -ENODEV because the hotplug port was hot-removed in-between
> the two function calls. In that case we'll emit both "Card present"
> *and* "Link Up" since both 1 and -ENODEV are considered "true". This
> is not the expected behavior. Those messages should be emited when
> "present" and "link_active" are positive.
>=20
> Signed-off-by: Bitao Hu <yaoma@linux.alibaba.com>
> Reviewed-by: Lukas Wunner <lukas@wunner.de>

Thanks for updaring the description.

Reviewed-by: Ilpo J=E4rvinen <ilpo.jarvinen@linux.intel.com>

--=20
 i.


> ---
> v1 -> v2:
> 1. Explain the rationale of the code change in the commit message
> more clearly.
> 2. Add the "Reviewed-by" tag of Lukas.
> ---
>  drivers/pci/hotplug/pciehp_ctrl.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>=20
> diff --git a/drivers/pci/hotplug/pciehp_ctrl.c b/drivers/pci/hotplug/pcie=
hp_ctrl.c
> index dcdbfcf404dd..6adfdbb70150 100644
> --- a/drivers/pci/hotplug/pciehp_ctrl.c
> +++ b/drivers/pci/hotplug/pciehp_ctrl.c
> @@ -276,10 +276,10 @@ void pciehp_handle_presence_or_link_change(struct c=
ontroller *ctrl, u32 events)
>  =09case OFF_STATE:
>  =09=09ctrl->state =3D POWERON_STATE;
>  =09=09mutex_unlock(&ctrl->state_lock);
> -=09=09if (present)
> +=09=09if (present > 0)
>  =09=09=09ctrl_info(ctrl, "Slot(%s): Card present\n",
>  =09=09=09=09  slot_name(ctrl));
> -=09=09if (link_active)
> +=09=09if (link_active > 0)
>  =09=09=09ctrl_info(ctrl, "Slot(%s): Link Up\n",
>  =09=09=09=09  slot_name(ctrl));
>  =09=09ctrl->request_result =3D pciehp_enable_slot(ctrl);
>=20
--8323328-1602990161-1716893227=:5869--