/share/man/man4/ehci.4

https://bitbucket.org/freebsd/freebsd-head/ · Forth · 101 lines · 101 code · 0 blank · 0 comment · 1 complexity · 1549c66ad11928a5eb00e7eee75a9421 MD5 · raw file

  1. .\" $NetBSD: ehci.4,v 1.8 2001/11/21 17:22:56 augustss Exp $
  2. .\"
  3. .\" Copyright (c) 2001 The NetBSD Foundation, Inc.
  4. .\" All rights reserved.
  5. .\"
  6. .\" This code is derived from software contributed to The NetBSD Foundation
  7. .\" by Lennart Augustsson.
  8. .\"
  9. .\" Redistribution and use in source and binary forms, with or without
  10. .\" modification, are permitted provided that the following conditions
  11. .\" are met:
  12. .\" 1. Redistributions of source code must retain the above copyright
  13. .\" notice, this list of conditions and the following disclaimer.
  14. .\" 2. Redistributions in binary form must reproduce the above copyright
  15. .\" notice, this list of conditions and the following disclaimer in the
  16. .\" documentation and/or other materials provided with the distribution.
  17. .\"
  18. .\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
  19. .\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
  20. .\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
  21. .\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
  22. .\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  23. .\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  24. .\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  25. .\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  26. .\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  27. .\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  28. .\" POSSIBILITY OF SUCH DAMAGE.
  29. .\"
  30. .\" $FreeBSD$
  31. .\"
  32. .Dd March 4, 2012
  33. .Dt EHCI 4
  34. .Os
  35. .Sh NAME
  36. .Nm ehci
  37. .Nd USB Enhanced Host Controller driver
  38. .Sh SYNOPSIS
  39. .Cd "device ehci"
  40. .Sh DESCRIPTION
  41. The
  42. .Nm
  43. driver provides support for the
  44. .Tn USB
  45. Enhanced Host Controller Interface,
  46. which is used by
  47. .Tn USB
  48. 2.0 controllers.
  49. .Pp
  50. .Tn EHCI
  51. controllers are peculiar in that they can only handle the
  52. .Tn USB
  53. 2.0 protocol.
  54. This means that they normally have one or more companion controllers
  55. (i.e.,
  56. .Xr ohci 4
  57. or
  58. .Xr uhci 4 )
  59. handling USB 1.x devices.
  60. Consequently each
  61. .Tn USB
  62. connector is electrically connected to two
  63. .Tn USB
  64. controllers.
  65. The handling of this is totally automatic,
  66. but can be noticed since
  67. .Tn USB
  68. 1.x and
  69. .Tn USB
  70. 2.0 devices plugged in to the same
  71. connector appear to connect to different USB busses.
  72. .Sh SEE ALSO
  73. .Xr xhci 4 ,
  74. .Xr ohci 4 ,
  75. .Xr uhci 4 ,
  76. .Xr usb 4
  77. .Sh HISTORY
  78. The
  79. .Nm
  80. device driver first appeared in
  81. .Fx 5.1 .
  82. .Sh LOADER TUNABLES
  83. When the kernel has been compiled with
  84. .Cd options USB_DEBUG ,
  85. some tunables become available that affect the behavior of
  86. .Nm .
  87. These tunables can be set at the
  88. .Xr loader 8
  89. prompt before booting the kernel or stored in
  90. .Xr loader.conf 5 .
  91. .Bl -tag -width "xxxxxx"
  92. .It Va hw.usb.ehci.lostintrbug
  93. This tunable enables the lost interrupt quirk.
  94. The default value is 0 (off).
  95. .It Va hw.usb.ehci.iaadbug
  96. This tunable enables the EHCI doorbell quirk.
  97. The default value is 0 (off).
  98. .It Va hw.usb.ehci.no_hs
  99. This tunable disables USB devices to attach like HIGH-speed ones and will force all attached devices to attach to the FULL- or LOW-speed companion controller.
  100. The default value is 0 (off).
  101. .El