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authorNicolas Kaiser <nikai@nikai.net>2011-05-23 14:59:56 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2011-05-23 18:14:11 -0400
commitf14d8d3a1618438c08eb74114c06b3307fac6436 (patch)
tree2b1667960ae91ea1a03f4d7de8974c7f9b9b92b0 /Documentation/vgaarbiter.txt
parent8208266060664726e9f998a9c57c2780549e460c (diff)
Documentation: fix vgaarbiter.txt typos etc.
Fixed typos. v2: Incorporated changes by Randy Dunlap. Signed-off-by: Nicolas Kaiser <nikai@nikai.net> Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation/vgaarbiter.txt')
-rw-r--r--Documentation/vgaarbiter.txt20
1 files changed, 9 insertions, 11 deletions
diff --git a/Documentation/vgaarbiter.txt b/Documentation/vgaarbiter.txt
index 43a9b0694fdd..b7d401e0eae9 100644
--- a/Documentation/vgaarbiter.txt
+++ b/Documentation/vgaarbiter.txt
@@ -14,11 +14,10 @@ the legacy VGA arbitration task (besides other bus management tasks) when more
14than one legacy device co-exists on the same machine. But the problem happens 14than one legacy device co-exists on the same machine. But the problem happens
15when these devices are trying to be accessed by different userspace clients 15when these devices are trying to be accessed by different userspace clients
16(e.g. two server in parallel). Their address assignments conflict. Moreover, 16(e.g. two server in parallel). Their address assignments conflict. Moreover,
17ideally, being an userspace application, it is not the role of the the X 17ideally, being a userspace application, it is not the role of the X server to
18server to control bus resources. Therefore an arbitration scheme outside of 18control bus resources. Therefore an arbitration scheme outside of the X server
19the X server is needed to control the sharing of these resources. This 19is needed to control the sharing of these resources. This document introduces
20document introduces the operation of the VGA arbiter implemented for Linux 20the operation of the VGA arbiter implemented for the Linux kernel.
21kernel.
22 21
23---------------------------------------------------------------------------- 22----------------------------------------------------------------------------
24 23
@@ -39,7 +38,7 @@ I.1 vgaarb
39The vgaarb is a module of the Linux Kernel. When it is initially loaded, it 38The vgaarb is a module of the Linux Kernel. When it is initially loaded, it
40scans all PCI devices and adds the VGA ones inside the arbitration. The 39scans all PCI devices and adds the VGA ones inside the arbitration. The
41arbiter then enables/disables the decoding on different devices of the VGA 40arbiter then enables/disables the decoding on different devices of the VGA
42legacy instructions. Device which do not want/need to use the arbiter may 41legacy instructions. Devices which do not want/need to use the arbiter may
43explicitly tell it by calling vga_set_legacy_decoding(). 42explicitly tell it by calling vga_set_legacy_decoding().
44 43
45The kernel exports a char device interface (/dev/vga_arbiter) to the clients, 44The kernel exports a char device interface (/dev/vga_arbiter) to the clients,
@@ -95,8 +94,8 @@ In the case of devices hot-{un,}plugged, there is a hook - pci_notify() - to
95notify them being added/removed in the system and automatically added/removed 94notify them being added/removed in the system and automatically added/removed
96in the arbiter. 95in the arbiter.
97 96
98There's also a in-kernel API of the arbiter in the case of DRM, vgacon and 97There is also an in-kernel API of the arbiter in case DRM, vgacon, or other
99others which may use the arbiter. 98drivers want to use it.
100 99
101 100
102I.2 libpciaccess 101I.2 libpciaccess
@@ -117,9 +116,8 @@ Besides it, in pci_system were added:
117 struct pci_device *vga_default_dev; 116 struct pci_device *vga_default_dev;
118 117
119 118
120The vga_count is usually need to keep informed how many cards are being 119The vga_count is used to track how many cards are being arbitrated, so for
121arbitrated, so for instance if there's only one then it can totally escape the 120instance, if there is only one card, then it can completely escape arbitration.
122scheme.
123 121
124 122
125These functions below acquire VGA resources for the given card and mark those 123These functions below acquire VGA resources for the given card and mark those