From: Lukas Wunner <lukas@wunner.de>
To: "Raj, Ashok" <ashok.raj@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>,
linux-pci@vger.kernel.org,
Sathyanarayanan Kuppuswamy <sathyanarayanan.kuppuswamy@intel.com>,
linux-kernel@vger.kernel.org
Subject: Re: [Patch v2 1/1] PCI: pciehp: Add support for handling MRL events
Date: Thu, 10 Dec 2020 21:57:19 +0100 [thread overview]
Message-ID: <20201210205719.GA25769@wunner.de> (raw)
In-Reply-To: <20201203225124.GA72369@otc-nc-03>
On Thu, Dec 03, 2020 at 02:51:24PM -0800, Raj, Ashok wrote:
> - Press ATTN,
> - Slot is empty
> - After 5 seconds synthetic PDC arrives.
> but since no presence and no link active, we leave slot in
> BLINKINGON_STATE, and led keeps blinking
>
> if someone were to add a card after the 5 seconds, no hot-add is processed
> since we don't get notifications for PDC events when ATTN exists.
>
> Can we automatically cancel the blinking and return slot back to OFF_STATE?
Yes.
> If the operation initiated by the attention button fails for any reason, it
> is recommended that system software present an error message explaining
> failure via a software user interface, or add the error message to system
> log.
Ah so we're supposed to log a message if the slot is empty.
That needs to be added then to the code snippet I sent you
yesterday in response to your off-list e-mail.
> Alternately we can also choose to subscribe to PDC, but ignore if slot is
> in OFF_STATE. So we let ATTN drive the add. But if PDC happens and we are
> in BLINKINGON_STATE, then we can process the hot-add? Spec says a software
> recommendation, but i think the cancel after 5 seconds seems better?
That approach seems more complicated. It's better to stop blinking
and return to OFF_STATE if after the 5 second interval the slot is
found to be empty.
Thanks,
Lukas
prev parent reply other threads:[~2020-12-10 21:08 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-22 1:42 [Patch v2 1/1] PCI: pciehp: Add support for handling MRL events Ashok Raj
2020-11-22 9:08 ` Lukas Wunner
2020-11-25 22:40 ` Raj, Ashok
2020-12-03 22:51 ` Raj, Ashok
2020-12-10 20:57 ` Lukas Wunner [this message]
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