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Date:   Mon, 3 Oct 2022 20:21:47 +0200
From:   Pali =?utf-8?B?Um9ow6Fy?= <pali@kernel.org>
To:     Jonathan Derrick <jonathan.derrick@linux.dev>,
        Vidya Sagar <vidyas@nvidia.com>,
        Bjorn Helgaas <helgaas@kernel.org>
Cc:     Lukas Wunner <lukas@wunner.de>, bhelgaas@google.com,
        robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org,
        lpieralisi@kernel.org, kw@linux.com, thierry.reding@gmail.com,
        jonathanh@nvidia.com, mani@kernel.org,
        Sergey.Semin@baikalelectronics.ru, jszhang@kernel.org,
        linux-pci@vger.kernel.org, linux-tegra@vger.kernel.org,
        linux-kernel@vger.kernel.org, devicetree@vger.kernel.org,
        kthota@nvidia.com, mmaddireddy@nvidia.com, sagar.tv@gmail.com,
        Marek =?utf-8?B?QmVow7pu?= <kabel@kernel.org>
Subject: Re: [PATCH V1 0/4] GPIO based PCIe Hot-Plug support
Message-ID: <20221003182147.jp5gn2jpnf4gucdl@pali>
References: <2a465222-342a-418b-95af-9948f6ce9065@linux.dev>
 <20221003180949.GA2104321@bhelgaas>
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On Monday 03 October 2022 13:09:49 Bjorn Helgaas wrote:
> On Sat, Oct 01, 2022 at 05:50:07PM -0600, Jonathan Derrick wrote:
> > On 10/1/2022 10:20 AM, Pali Rohár wrote:
> > ...
> 
> > > Would not it better to rather synthesise PCIe Slot Capabilities support
> > > in your PCIe Root Port device (e.g. via pci-bridge-emul.c) and then let
> > > existing PCI hotplug code to take care for hotplugging? Because it
> > > already implements all required stuff for re-scanning, registering and
> > > unregistering PCIe devices for Root Ports with Slot Capabilities. And I
> > > think that there is no need to have just another (GPIO based)
> > > implementation of PCI hotplug.
> >
> > I did that a few years ago (rejected), but can attest to the robustness of
> > the pcie hotplug code on non-hotplug slots.
> > https://lwn.net/Articles/811988/
> 
> I think the thread is here:
> https://lore.kernel.org/linux-pci/1581120007-5280-1-git-send-email-jonathan.derrick@intel.com/
> and I'm sorry that my response came across as "rejected".  I intended
> it as "this is good ideas and good work and we should keep going".
> 
> Bjorn

Nice! So we have consensus that this is a good idea. Anyway, if you need
help with designing something here, please let me know as I have good
understanding of all (just two) consumers of pci-bridge-emul.c driver.