From: Bjorn Helgaas <helgaas@kernel.org>
To: Sergei Miroshnichenko <s.miroshnichenko@yadro.com>
Cc: "linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux@yadro.com" <linux@yadro.com>, "sr@denx.de" <sr@denx.de>
Subject: Re: [PATCH v7 09/26] PCI: hotplug: Calculate immovable parts of bridge windows
Date: Fri, 31 Jan 2020 14:10:45 -0600 [thread overview]
Message-ID: <20200131201045.GA67143@google.com> (raw)
In-Reply-To: <c9112d99415bdbd626362c63a3c473bafcc5ec26.camel@yadro.com>
On Fri, Jan 31, 2020 at 04:59:44PM +0000, Sergei Miroshnichenko wrote:
> On Thu, 2020-01-30 at 15:26 -0600, Bjorn Helgaas wrote:
> > On Wed, Jan 29, 2020 at 06:29:20PM +0300, Sergei Miroshnichenko
> > wrote:
> > > When movable BARs are enabled, and if a bridge contains a device
> > > with fixed
> > > (IORESOURCE_PCI_FIXED) or immovable BARs, the corresponding windows
> > > can't
> >
> > What is the difference between fixed (IORESOURCE_PCI_FIXED) and
> > immovable BARs? I'm hesitant to add a new concept ("immovable") with
> > a different name but very similar meaning.
> >
> > I understand that in the case of bridge windows, you may need to
> > track
> > only part of the window, as opposed to a BAR where the entire BAR has
> > to be either fixed or movable, but I think adding a new term will be
> > confusing.
>
> I thought the term "fixed BAR" has some legacy scent, and those marked
> with flag IORESOURCE_PCI_FIXED are fixed forever. But a BAR may become
> movable after rmmod-ing its driver that didn't support movable BARs.
>
> Still, the IORESOURCE_PCI_FIXED is used just a few times in the kernel,
> so the "fixed BAR" term is probably not so well-established, so I don't
> mind referring all non-movables as "fixed": both marked with the flag
> and not. Will change all of them in v8.
Yeah, "fixed" is a relatively new idea and not part of the actual
spec. And you're right that "immovable" is slightly different because
sometimes it's a consequence of lack of driver support.
This probably isn't a big deal either way. I think there are two
cases: (a) IORESOURCE_PCI_FIXED resources (i.e., legacy things that
can't be changed because they don't have BARs) and (b) BARs that can't
be changed because there's a driver bound that doesn't support moving
them. Either way, we have to treat them the same for resource
allocation, so I'm not sure it's worth differentiating at this level.
Bjorn
next prev parent reply other threads:[~2020-01-31 20:10 UTC|newest]
Thread overview: 48+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-29 15:29 [PATCH v7 00/26] PCI: Allow BAR movement during boot and hotplug Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 01/26] PCI: Fix race condition in pci_enable/disable_device() Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 02/26] PCI: Enable bridge's I/O and MEM access for hotplugged devices Sergei Miroshnichenko
2020-01-30 23:12 ` Bjorn Helgaas
2020-01-29 15:29 ` [PATCH v7 03/26] PCI: hotplug: Initial support of the movable BARs feature Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 04/26] PCI: Add version of release_child_resources() aware of immovable BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 05/26] PCI: hotplug: Fix reassigning the released BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 06/26] PCI: hotplug: Recalculate every bridge window during rescan Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 07/26] PCI: hotplug: Don't allow hot-added devices to steal resources Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 08/26] PCI: hotplug: Try to reassign movable BARs only once Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 09/26] PCI: hotplug: Calculate immovable parts of bridge windows Sergei Miroshnichenko
2020-01-30 21:26 ` Bjorn Helgaas
2020-01-31 16:59 ` Sergei Miroshnichenko
2020-01-31 20:10 ` Bjorn Helgaas [this message]
2020-01-29 15:29 ` [PATCH v7 10/26] PCI: Include fixed and immovable BARs into the bus size calculating Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 11/26] PCI: hotplug: movable BARs: Compute limits for relocated bridge windows Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 12/26] PCI: Make sure bridge windows include their fixed BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 13/26] PCI: hotplug: Add support of immovable BARs to pci_assign_resource() Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 14/26] PCI: hotplug: Sort immovable BARs before assignment Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 15/26] PCI: hotplug: Enable the movable BARs feature by default Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 16/26] PCI: Ignore PCIBIOS_MIN_MEM Sergei Miroshnichenko
2020-01-30 23:52 ` Bjorn Helgaas
2020-01-31 18:19 ` Sergei Miroshnichenko
2020-01-31 20:27 ` Bjorn Helgaas
2020-02-05 13:04 ` Sergei Miroshnichenko
2020-02-05 16:32 ` Bjorn Helgaas
2020-02-12 12:16 ` Sergei Miroshnichenko
2020-02-12 14:13 ` Bjorn Helgaas
2020-01-29 15:29 ` [PATCH v7 17/26] PCI: hotplug: Ignore the MEM BAR offsets from BIOS/bootloader Sergei Miroshnichenko
2020-01-31 20:31 ` Bjorn Helgaas
2020-02-05 11:01 ` Sergei Miroshnichenko
2020-02-05 16:42 ` Bjorn Helgaas
2020-02-12 12:29 ` Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 18/26] PCI: Treat VGA BARs as immovable Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 19/26] PCI: hotplug: Configure MPS for hot-added bridges during bus rescan Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 20/26] PNP: Don't reserve BARs for PCI when enabled movable BARs Sergei Miroshnichenko
2020-01-30 14:39 ` Rafael J. Wysocki
2020-01-30 21:14 ` Bjorn Helgaas
2020-01-31 15:48 ` Sergei Miroshnichenko
2020-01-31 19:39 ` Bjorn Helgaas
2020-01-29 15:29 ` [PATCH v7 21/26] PCI: hotplug: Don't disable the released bridge windows immediately Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 22/26] PCI: pciehp: Trigger a domain rescan on hp events when enabled movable BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 23/26] PCI: Don't claim immovable BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 24/26] PCI: hotplug: Don't reserve bus space when enabled movable BARs Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 25/26] nvme-pci: Handle " Sergei Miroshnichenko
2020-01-29 15:29 ` [PATCH v7 26/26] PCI/portdrv: Declare support of " Sergei Miroshnichenko
2020-01-30 23:37 ` [PATCH v7 00/26] PCI: Allow BAR movement during boot and hotplug Bjorn Helgaas
2020-02-03 4:56 ` Oliver O'Halloran
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20200131201045.GA67143@google.com \
--to=helgaas@kernel.org \
--cc=linux-pci@vger.kernel.org \
--cc=linux@yadro.com \
--cc=s.miroshnichenko@yadro.com \
--cc=sr@denx.de \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).