From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Bjorn Helgaas <helgaas@kernel.org>, Daniel Axtens <dja@axtens.net>
Cc: linux-pci@vger.kernel.org, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org,
gabriele.paoloni@huawei.com, airlied@linux.ie,
will.deacon@arm.com, dri-devel@lists.freedesktop.org,
z.liuxinliang@hisilicon.com, bhelgaas@google.com,
alex.williamson@redhat.com, lukas@wunner.de,
catalin.marinas@arm.com, zourongrong@gmail.com,
daniel.vetter@intel.com
Subject: Re: [PATCH v2 1/1] Split VGA default device handler out of VGA arbiter
Date: Sun, 20 Aug 2017 12:08:20 -0700 [thread overview]
Message-ID: <1503256100.12059.13.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170819154753.GQ28977@bhelgaas-glaptop.roam.corp.google.com>
On Sat, 2017-08-19 at 10:47 -0500, Bjorn Helgaas wrote:
> So if ARM64 doesn't have these PCI legacy resources, does that mean an
> ARM64 host bridge cannot generate these legacy addresses on PCI? That
> is, there's no host bridge window that maps to those PCI addresses?
> That seems like a curious restriction on host bridges, but I guess it
> would be possible.
It's rather common. For example on POWER8:
- There is no IO space at all
- We configure the 32-bit MMIO window to be around 3..4G (to avoid
overlapping with DMA space below it).
So we effectively have no path to the legacy areas, and that hasn't
been a problem so far.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: benh@kernel.crashing.org (Benjamin Herrenschmidt)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 1/1] Split VGA default device handler out of VGA arbiter
Date: Sun, 20 Aug 2017 12:08:20 -0700 [thread overview]
Message-ID: <1503256100.12059.13.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170819154753.GQ28977@bhelgaas-glaptop.roam.corp.google.com>
On Sat, 2017-08-19 at 10:47 -0500, Bjorn Helgaas wrote:
> So if ARM64 doesn't have these PCI legacy resources, does that mean an
> ARM64 host bridge cannot generate these legacy addresses on PCI? That
> is, there's no host bridge window that maps to those PCI addresses?
> That seems like a curious restriction on host bridges, but I guess it
> would be possible.
It's rather common. For example on POWER8:
- There is no IO space at all
- We configure the 32-bit MMIO window to be around 3..4G (to avoid
overlapping with DMA space below it).
So we effectively have no path to the legacy areas, and that hasn't
been a problem so far.
Cheers,
Ben.
WARNING: multiple messages have this Message-ID (diff)
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Bjorn Helgaas <helgaas@kernel.org>, Daniel Axtens <dja@axtens.net>
Cc: gabriele.paoloni@huawei.com, airlied@linux.ie,
linux-pci@vger.kernel.org, will.deacon@arm.com,
dri-devel@lists.freedesktop.org, z.liuxinliang@hisilicon.com,
zourongrong@gmail.com, alex.williamson@redhat.com,
lukas@wunner.de, catalin.marinas@arm.com, bhelgaas@google.com,
daniel.vetter@intel.com, linuxppc-dev@lists.ozlabs.org,
linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 1/1] Split VGA default device handler out of VGA arbiter
Date: Sun, 20 Aug 2017 12:08:20 -0700 [thread overview]
Message-ID: <1503256100.12059.13.camel@kernel.crashing.org> (raw)
In-Reply-To: <20170819154753.GQ28977@bhelgaas-glaptop.roam.corp.google.com>
On Sat, 2017-08-19 at 10:47 -0500, Bjorn Helgaas wrote:
> So if ARM64 doesn't have these PCI legacy resources, does that mean an
> ARM64 host bridge cannot generate these legacy addresses on PCI? That
> is, there's no host bridge window that maps to those PCI addresses?
> That seems like a curious restriction on host bridges, but I guess it
> would be possible.
It's rather common. For example on POWER8:
- There is no IO space at all
- We configure the 32-bit MMIO window to be around 3..4G (to avoid
overlapping with DMA space below it).
So we effectively have no path to the legacy areas, and that hasn't
been a problem so far.
Cheers,
Ben.
next prev parent reply other threads:[~2017-08-20 19:08 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-17 11:30 [PATCH v2 0/1] Split VGA default nomination out from VGA arbiter Daniel Axtens
2017-08-17 11:30 ` Daniel Axtens
2017-08-17 11:30 ` Daniel Axtens
2017-08-17 11:30 ` [PATCH v2 1/1] Split VGA default device handler out of " Daniel Axtens
2017-08-17 11:30 ` Daniel Axtens
2017-08-17 11:30 ` Daniel Axtens
2017-08-18 7:38 ` Daniel Vetter
2017-08-18 7:38 ` Daniel Vetter
2017-08-18 7:38 ` Daniel Vetter
2017-08-19 15:47 ` Bjorn Helgaas
2017-08-19 15:47 ` Bjorn Helgaas
2017-08-19 15:47 ` Bjorn Helgaas
2017-08-20 19:08 ` Benjamin Herrenschmidt [this message]
2017-08-20 19:08 ` Benjamin Herrenschmidt
2017-08-20 19:08 ` Benjamin Herrenschmidt
2017-08-20 21:54 ` Bjorn Helgaas
2017-08-20 21:54 ` Bjorn Helgaas
2017-08-20 21:54 ` Bjorn Helgaas
2017-08-21 10:53 ` Lorenzo Pieralisi
2017-08-21 10:53 ` Lorenzo Pieralisi
2017-08-21 10:53 ` Lorenzo Pieralisi
2017-08-22 22:19 ` Bjorn Helgaas
2017-08-22 22:19 ` Bjorn Helgaas
2017-08-22 22:19 ` Bjorn Helgaas
2017-08-23 13:48 ` Ard Biesheuvel
2017-08-23 13:48 ` Ard Biesheuvel
2017-08-23 13:57 ` Bjorn Helgaas
2017-08-23 13:57 ` Bjorn Helgaas
2017-08-23 13:57 ` Bjorn Helgaas
2017-08-24 0:57 ` Dave Airlie
2017-08-24 0:57 ` Dave Airlie
2017-08-24 9:38 ` Ard Biesheuvel
2017-08-24 9:38 ` Ard Biesheuvel
2017-08-24 13:57 ` Bjorn Helgaas
2017-08-24 13:57 ` Bjorn Helgaas
2017-08-24 13:57 ` Bjorn Helgaas
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=1503256100.12059.13.camel@kernel.crashing.org \
--to=benh@kernel.crashing.org \
--cc=airlied@linux.ie \
--cc=alex.williamson@redhat.com \
--cc=bhelgaas@google.com \
--cc=catalin.marinas@arm.com \
--cc=daniel.vetter@intel.com \
--cc=dja@axtens.net \
--cc=dri-devel@lists.freedesktop.org \
--cc=gabriele.paoloni@huawei.com \
--cc=helgaas@kernel.org \
--cc=linux-arm-kernel@lists.infradead.org \
--cc=linux-pci@vger.kernel.org \
--cc=linuxppc-dev@lists.ozlabs.org \
--cc=lukas@wunner.de \
--cc=will.deacon@arm.com \
--cc=z.liuxinliang@hisilicon.com \
--cc=zourongrong@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.