From: "Derrick, Jonathan" <jonathan.derrick@intel.com>
To: "hch@lst.de" <hch@lst.de>
Cc: "Shevchenko, Andriy" <andriy.shevchenko@intel.com>,
"lorenzo.pieralisi@arm.com" <lorenzo.pieralisi@arm.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"mika.westerberg@linux.intel.com"
<mika.westerberg@linux.intel.com>,
"Baldysiak, Pawel" <pawel.baldysiak@intel.com>,
"helgaas@kernel.org" <helgaas@kernel.org>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"mr.nuke.me@gmail.com" <mr.nuke.me@gmail.com>,
"kbusch@kernel.org" <kbusch@kernel.org>,
"okaya@kernel.org" <okaya@kernel.org>
Subject: Re: [RFC 0/9] PCIe Hotplug Slot Emulation driver
Date: Mon, 10 Feb 2020 17:09:59 +0000 [thread overview]
Message-ID: <8a787f85964c66e8c6efde51f439db26fecfc5c6.camel@intel.com> (raw)
In-Reply-To: <20200210165857.GA19419@lst.de>
On Mon, 2020-02-10 at 17:58 +0100, hch@lst.de wrote:
> On Mon, Feb 10, 2020 at 03:05:47PM +0000, Derrick, Jonathan wrote:
> > > The code seems like one giant hack to me. What is the real life
> > > use case for this? Another Intel chipset fuckup like vmd or the ahci
> > > remapping?
> > >
> > Exactly as the cover letter describes. An interposer being used on a
> > non-hotplug slot.
>
> That isn't a use a case, that iѕ a description of the implementation.
> Why would you want this code?
It allows non-hotplug slots to take advantage of the kernel's robust
hotplug ecosystem, if the platform configuration can tolerate the
events. This could also reduce BOM cost by eliminating some slot
controllers. Say you had something that only needed to be hotplugged
very infrequently, like RAIDed OS drives, versus something needing to
be hotplugged very frequently like data drives.
Granted it probably could be fit into pciehp_poll, but it seemed to
have a different objective (emulating slot)
next prev parent reply other threads:[~2020-02-10 17:10 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-07 23:59 [RFC 0/9] PCIe Hotplug Slot Emulation driver Jon Derrick
2020-02-07 23:59 ` [RFC 1/9] PCI: pci-bridge-emul: Update PCIe register behaviors Jon Derrick
2020-02-08 9:55 ` Andy Shevchenko
2020-03-28 21:42 ` Bjorn Helgaas
2020-02-08 0:00 ` [RFC 2/9] PCI: pci-bridge-emul: Eliminate reserved member Jon Derrick
2020-03-28 21:43 ` Bjorn Helgaas
2020-02-08 0:00 ` [RFC 3/9] PCI: pci-bridge-emul: Provide a helper to set behavior Jon Derrick
2020-02-08 0:00 ` [RFC 4/9] PCI: pciehp: Indirect slot register operations Jon Derrick
2020-02-08 0:00 ` [RFC 5/9] PCI: Add pcie_port_slot_emulated stub Jon Derrick
2020-02-08 0:00 ` [RFC 6/9] PCI: pciehp: Expose the poll loop to other drivers Jon Derrick
2020-02-08 0:00 ` [RFC 7/9] PCI: Move pci_dev_str_match to search.c Jon Derrick
2020-02-08 0:00 ` [RFC 8/9] PCI: pciehp: Add hotplug slot emulation driver Jon Derrick
2020-02-08 0:00 ` [RFC 9/9] PCI: pciehp: Wire up pcie_port_emulate_slot and pciehp_emul Jon Derrick
2020-02-10 7:01 ` [RFC 0/9] PCIe Hotplug Slot Emulation driver Christoph Hellwig
2020-02-10 15:05 ` Derrick, Jonathan
2020-02-10 16:58 ` hch
2020-02-10 17:09 ` Derrick, Jonathan [this message]
2020-03-28 21:51 ` Bjorn Helgaas
2020-03-30 17:43 ` Derrick, Jonathan
2020-03-30 17:49 ` hch
2020-04-01 21:45 ` Bjorn Helgaas
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