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

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>

authored by

Mauro Carvalho Chehab and committed by
Jonathan Corbet
a557f67c 729979eb

+9 -9
+9 -9
Documentation/PCI/acpi-info.rst
··· 22 22 controllers and a _PRT is needed to describe those connections. 23 23 24 24 ACPI resource description is done via _CRS objects of devices in the ACPI 25 - namespace [2].   The _CRS is like a generalized PCI BAR: the OS can read 25 + namespace [2]. The _CRS is like a generalized PCI BAR: the OS can read 26 26 _CRS and figure out what resource is being consumed even if it doesn't have 27 - a driver for the device [3].  That's important because it means an old OS 27 + a driver for the device [3]. That's important because it means an old OS 28 28 can work correctly even on a system with new devices unknown to the OS. 29 29 The new devices might not do anything, but the OS can at least make sure no 30 30 resources conflict with them. ··· 41 41 driver to bind to it, and the _CRS tells the OS and the driver where the 42 42 device's registers are. 43 43 44 - PCI host bridges are PNP0A03 or PNP0A08 devices.  Their _CRS should 45 - describe all the address space they consume.  This includes all the windows 44 + PCI host bridges are PNP0A03 or PNP0A08 devices. Their _CRS should 45 + describe all the address space they consume. This includes all the windows 46 46 they forward down to the PCI bus, as well as registers of the host bridge 47 - itself that are not forwarded to PCI.  The host bridge registers include 47 + itself that are not forwarded to PCI. The host bridge registers include 48 48 things like secondary/subordinate bus registers that determine the bus 49 49 range below the bridge, window registers that describe the apertures, etc. 50 50 These are all device-specific, non-architected things, so the only way a 51 51 PNP0A03/PNP0A08 driver can manage them is via _PRS/_CRS/_SRS, which contain 52 - the device-specific details.  The host bridge registers also include ECAM 52 + the device-specific details. The host bridge registers also include ECAM 53 53 space, since it is consumed by the host bridge. 54 54 55 55 ACPI defines a Consumer/Producer bit to distinguish the bridge registers ··· 66 66 bridge registers (including ECAM space) in PNP0C02 catch-all devices [6]. 67 67 With the exception of ECAM, the bridge register space is device-specific 68 68 anyway, so the generic PNP0A03/PNP0A08 driver (pci_root.c) has no need to 69 - know about it.   69 + know about it. 70 70 71 71 New architectures should be able to use "Consumer" Extended Address Space 72 72 descriptors in the PNP0A03 device for bridge registers, including ECAM, ··· 75 75 Extended Address Space ones, are windows, so it would not be safe to 76 76 describe bridge registers this way on those architectures. 77 77 78 - PNP0C02 "motherboard" devices are basically a catch-all.  There's no 78 + PNP0C02 "motherboard" devices are basically a catch-all. There's no 79 79 programming model for them other than "don't use these resources for 80 - anything else."  So a PNP0C02 _CRS should claim any address space that is 80 + anything else." So a PNP0C02 _CRS should claim any address space that is 81 81 (1) not claimed by _CRS under any other device object in the ACPI namespace 82 82 and (2) should not be assigned by the OS to something else. 83 83