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Documentation: fix vgaarbiter.txt typos etc.

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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>
This commit is contained in:
Nicolas Kaiser 2011-05-23 11:59:56 -07:00 committed by Linus Torvalds
parent 8208266060
commit f14d8d3a16
1 changed files with 9 additions and 11 deletions
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20
Documentation/vgaarbiter.txt
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@ -14,11 +14,10 @@ the legacy VGA arbitration task (besides other bus management tasks) when more
than one legacy device co-exists on the same machine. But the problem happens than one legacy device co-exists on the same machine. But the problem happens
when these devices are trying to be accessed by different userspace clients when these devices are trying to be accessed by different userspace clients
(e.g. two server in parallel). Their address assignments conflict. Moreover, (e.g. two server in parallel). Their address assignments conflict. Moreover,
ideally, being an userspace application, it is not the role of the the X ideally, being a userspace application, it is not the role of the X server to
server to control bus resources. Therefore an arbitration scheme outside of control bus resources. Therefore an arbitration scheme outside of the X server
the X server is needed to control the sharing of these resources. This is needed to control the sharing of these resources. This document introduces
document introduces the operation of the VGA arbiter implemented for Linux the operation of the VGA arbiter implemented for the Linux kernel.
kernel.
---------------------------------------------------------------------------- ----------------------------------------------------------------------------
@ -39,7 +38,7 @@ I.1 vgaarb
The vgaarb is a module of the Linux Kernel. When it is initially loaded, it The vgaarb is a module of the Linux Kernel. When it is initially loaded, it
scans all PCI devices and adds the VGA ones inside the arbitration. The scans all PCI devices and adds the VGA ones inside the arbitration. The
arbiter then enables/disables the decoding on different devices of the VGA arbiter then enables/disables the decoding on different devices of the VGA
legacy instructions. Device which do not want/need to use the arbiter may legacy instructions. Devices which do not want/need to use the arbiter may
explicitly tell it by calling vga_set_legacy_decoding(). explicitly tell it by calling vga_set_legacy_decoding().
The kernel exports a char device interface (/dev/vga_arbiter) to the clients, The 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
notify them being added/removed in the system and automatically added/removed notify them being added/removed in the system and automatically added/removed
in the arbiter. in the arbiter.
There's also a in-kernel API of the arbiter in the case of DRM, vgacon and There is also an in-kernel API of the arbiter in case DRM, vgacon, or other
others which may use the arbiter. drivers want to use it.
I.2 libpciaccess I.2 libpciaccess
@ -117,9 +116,8 @@ Besides it, in pci_system were added:
struct pci_device *vga_default_dev; struct pci_device *vga_default_dev;
The vga_count is usually need to keep informed how many cards are being The vga_count is used to track how many cards are being arbitrated, so for
arbitrated, so for instance if there's only one then it can totally escape the instance, if there is only one card, then it can completely escape arbitration.
scheme.
These functions below acquire VGA resources for the given card and mark those These functions below acquire VGA resources for the given card and mark those