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docs: PCI: Replace non-breaking spaces to avoid PDF issues

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The conversion tools used during DocBook/LaTeX/html/Markdown->ReST
conversion and some cut-and-pasted text contain some characters that
aren't easily reachable on standard keyboards and/or could cause
troubles when parsed by the documentation build system.

Replace the occurences of the following characters:

	- U+00a0 (' '): NO-BREAK SPACE
	  as it can cause lines being truncated on PDF output

Acked-by: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/8036126a59adb720dbc9233341ad5a08531cf73f.1623826294.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
This commit is contained in:
Mauro Carvalho Chehab 2021-06-16 08:55:14 +02:00 committed by Jonathan Corbet
parent 729979ebef
commit a557f67cd7
1 changed files with 9 additions and 9 deletions
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18
Documentation/PCI/acpi-info.rst
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@ -22,9 +22,9 @@ or if the device has INTx interrupts connected by platform interrupt
controllers and a _PRT is needed to describe those connections.
ACPI resource description is done via _CRS objects of devices in the ACPI
namespace [2].   The _CRS is like a generalized PCI BAR: the OS can read
namespace [2]. The _CRS is like a generalized PCI BAR: the OS can read
_CRS and figure out what resource is being consumed even if it doesn't have
a driver for the device [3].  That's important because it means an old OS
a driver for the device [3]. That's important because it means an old OS
can work correctly even on a system with new devices unknown to the OS.
The new devices might not do anything, but the OS can at least make sure no
resources conflict with them.
@ -41,15 +41,15 @@ ACPI, that device will have a specific _HID/_CID that tells the OS what
driver to bind to it, and the _CRS tells the OS and the driver where the
device's registers are.
PCI host bridges are PNP0A03 or PNP0A08 devices.  Their _CRS should
describe all the address space they consume.  This includes all the windows
PCI host bridges are PNP0A03 or PNP0A08 devices. Their _CRS should
describe all the address space they consume. This includes all the windows
they forward down to the PCI bus, as well as registers of the host bridge
itself that are not forwarded to PCI.  The host bridge registers include
itself that are not forwarded to PCI. The host bridge registers include
things like secondary/subordinate bus registers that determine the bus
range below the bridge, window registers that describe the apertures, etc.
These are all device-specific, non-architected things, so the only way a
PNP0A03/PNP0A08 driver can manage them is via _PRS/_CRS/_SRS, which contain
the device-specific details.  The host bridge registers also include ECAM
the device-specific details. The host bridge registers also include ECAM
space, since it is consumed by the host bridge.
ACPI defines a Consumer/Producer bit to distinguish the bridge registers
@ -66,7 +66,7 @@ the PNP0A03/PNP0A08 device itself. The workaround was to describe the
bridge registers (including ECAM space) in PNP0C02 catch-all devices [6].
With the exception of ECAM, the bridge register space is device-specific
anyway, so the generic PNP0A03/PNP0A08 driver (pci_root.c) has no need to
know about it.  
know about it.
New architectures should be able to use "Consumer" Extended Address Space
descriptors in the PNP0A03 device for bridge registers, including ECAM,
@ -75,9 +75,9 @@ ia64 kernels assume all address space descriptors, including "Consumer"
Extended Address Space ones, are windows, so it would not be safe to
describe bridge registers this way on those architectures.
PNP0C02 "motherboard" devices are basically a catch-all.  There's no
PNP0C02 "motherboard" devices are basically a catch-all. There's no
programming model for them other than "don't use these resources for
anything else."  So a PNP0C02 _CRS should claim any address space that is
anything else." So a PNP0C02 _CRS should claim any address space that is
(1) not claimed by _CRS under any other device object in the ACPI namespace
and (2) should not be assigned by the OS to something else.