From: Bjorn Helgaas <helgaas@kernel.org>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>,
Sinan Kaya <okaya@kernel.org>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
linux-pci@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
"Zilberman, Zeev" <zeev@amazon.com>,
"Saidi, Ali" <alisaidi@amazon.com>
Subject: Re: [PATCH/RESEND] arm64: acpi/pci: invoke _DSM whether to preserve firmware PCI setup
Date: Wed, 12 Jun 2019 08:27:30 -0500 [thread overview]
Message-ID: <20190612132730.GB13533@google.com> (raw)
In-Reply-To: <97fd2516fdde7f9f01688af426c103806f68dd2c.camel@kernel.crashing.org>
On Wed, Jun 12, 2019 at 10:06:06AM +1000, Benjamin Herrenschmidt wrote:
> On Tue, 2019-06-11 at 18:39 -0500, Bjorn Helgaas wrote:
> > This is fine, but can we make a tiny step toward doing this in generic
> > code instead of adding more arch-specific stuff?
> >
> > E.g., evaluate the _DSM in the generic acpi_pci_root_add(), set a
> > "preserve_config" bit in the struct acpi_pci_root, and test the bit
> > here?
>
> I'd rather have the flag in the host bridge no ?
Oh, of course, that would make more sense.
> Talking of which, look at the ongoing discussion I have with Lorenzo
> when it comes to pci_bus_claim_resources vs. what x86 does, I'd love
> for you to chime in. I'd like to try to consolidate things further
> accross architectures but there might be reasons I don't see as to why
> things are different in that area, so ...
I don't know any reasons why things are different per arch. In most
cases I suspect FUD.
Speaking of which, *this* patch looks like FUD because it essentially
says "Linux shouldn't change the PCI configuration on this system" but
it offers no explanation of *why* the config needs to be preserved. I
would really like some note like "run-time firmware depends on the
addresses of device X".
Bjorn
next prev parent reply other threads:[~2019-06-12 13:27 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-03 23:41 [RFC] ARM64 PCI resource survey issue(s) Benjamin Herrenschmidt
2019-06-04 1:49 ` Bjorn Helgaas
2019-06-04 3:32 ` Benjamin Herrenschmidt
2019-06-04 3:37 ` Benjamin Herrenschmidt
2019-06-04 6:56 ` Benjamin Herrenschmidt
2019-06-04 12:49 ` Bjorn Helgaas
2019-06-04 20:41 ` Benjamin Herrenschmidt
2019-06-06 9:00 ` [PATCH/RESEND] arm64: acpi/pci: invoke _DSM whether to preserve firmware PCI setup Benjamin Herrenschmidt
2019-06-06 9:13 ` Ard Biesheuvel
2019-06-06 10:55 ` Benjamin Herrenschmidt
2019-06-11 14:31 ` Lorenzo Pieralisi
2019-06-11 22:09 ` Benjamin Herrenschmidt
2019-06-11 22:34 ` Ard Biesheuvel
2019-06-11 22:40 ` Benjamin Herrenschmidt
2019-06-12 10:21 ` Lorenzo Pieralisi
2019-06-12 22:05 ` Benjamin Herrenschmidt
2019-06-11 14:58 ` Lorenzo Pieralisi
2019-06-11 22:19 ` Benjamin Herrenschmidt
2019-06-12 10:08 ` Lorenzo Pieralisi
2019-06-12 10:58 ` Benjamin Herrenschmidt
2019-06-11 23:39 ` Bjorn Helgaas
2019-06-12 0:06 ` Benjamin Herrenschmidt
2019-06-12 13:27 ` Bjorn Helgaas [this message]
2019-06-12 21:46 ` Benjamin Herrenschmidt
2019-06-12 23:58 ` Benjamin Herrenschmidt
2019-06-10 10:11 ` [RFC] ARM64 PCI resource survey issue(s) Lorenzo Pieralisi
2019-06-11 5:46 ` Benjamin Herrenschmidt
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