From: Vidya Sagar <vidyas@nvidia.com>
To: "Bjorn Helgaas" <helgaas@kernel.org>,
lpieralisi@kernel.org, "Pali Rohár" <pali@kernel.org>,
"Jonathan Derrick" <jonathan.derrick@linux.dev>
Cc: "Lukas Wunner" <lukas@wunner.de>,
bhelgaas@google.com, robh+dt@kernel.org,
krzysztof.kozlowski+dt@linaro.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 Behún" <kabel@kernel.org>
Subject: Re: [PATCH V1 0/4] GPIO based PCIe Hot-Plug support
Date: Mon, 17 Oct 2022 08:16:06 +0530 [thread overview]
Message-ID: <38c1d688-1488-3ecb-422e-fbc47106c144@nvidia.com> (raw)
In-Reply-To: <9210e81f-15ee-6c54-bfbb-1188da48dd68@nvidia.com>
On 10/10/2022 11:44 AM, Vidya Sagar wrote:
>
>
> On 10/4/2022 9:34 AM, Vidya Sagar wrote:
>>
>>
>> On 10/3/2022 11:51 PM, Pali Rohár wrote:
>>> External email: Use caution opening links or attachments
>>>
>>>
>>> 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.
>>>
>>
>> Thanks all for your comments.
>>
>> I would like to hear from Bjorn / Lorenzo if the design of the current
>> patch series is fine at a high level or I should explore emulating the
>> root port's configuration space to fake slot config/control registers
>> (which in turn depend on the hotplug GPIO interrupt & state to update
>> Presence Detect related bits in Slot status register) and use the PCIe
>> native Hot-plug framework itself to carry out with enabling the
>> Hot-plug functionality?
>
> Bjorn / Lorenzo,
> Could you please take time to comment on the discussion happened here
> and the right approach to be followed?
I'm really sorry to bug you on this, but would like to hear your
comments on the approach to be taken. So, I would really like to hear
your take on this.
Thanks,
Vidya Sagar
>
> Thanks,
> Vidya Sagar
>
>>
>> Thanks,
>> Vidya Sagar
>>
>>
next prev parent reply other threads:[~2022-10-17 2:46 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-09-30 19:27 [PATCH V1 0/4] GPIO based PCIe Hot-Plug support Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 1/4] dt-bindings: Add "hotplug-gpios" PCIe property Vidya Sagar
2022-10-01 15:56 ` Lukas Wunner
2022-10-01 16:10 ` Pali Rohár
2022-09-30 19:27 ` [PATCH V1 2/4] PCI/hotplug: Add GPIO PCIe hotplug driver Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 3/4] PCI: tegra194: Add support to configure a pluggable slot Vidya Sagar
2022-09-30 19:27 ` [PATCH V1 4/4] PCI: tegra194: Enable GPIO based Hot-Plug support Vidya Sagar
2022-10-01 16:00 ` [PATCH V1 0/4] GPIO based PCIe " Lukas Wunner
2022-10-01 16:20 ` Pali Rohár
2022-10-01 23:50 ` Jonathan Derrick
2022-10-03 18:09 ` Bjorn Helgaas
2022-10-03 18:21 ` Pali Rohár
2022-10-03 19:18 ` Jonathan Derrick
2022-10-04 4:04 ` Vidya Sagar
2022-10-10 6:14 ` Vidya Sagar
2022-10-17 2:46 ` Vidya Sagar [this message]
2022-11-09 15:35 ` Manivannan Sadhasivam
2022-10-03 17:04 ` Rob Herring
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