Mercurial Mercurial > oss > MCL > sftools > depl > docscontent / annotate
summary | shortlog | changelog | graph | tags | bookmarks | branches | files | changeset | file | latest | revisions | annotate | diff | comparison | raw | help
Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
Adaptation/GUID-FBE6E61F-5A2E-5A7A-BC59-51F072EBED7D.dita
author Graeme Price <GRAEME.PRICE@NOKIA.COM>
Fri, 15 Oct 2010 14:32:18 +0100
changeset 15 307f4279f433
permissions -rw-r--r--
Initial contribution of the Adaptation Documentation.
Ignore whitespace changes - Everywhere: Within whitespace: At end of lines:
15
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     1
 
<?xml version="1.0" encoding="utf-8"?>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     2
 
<!-- Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies) All rights reserved. -->
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     3
 
<!-- This component and the accompanying materials are made available under the terms of the License
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     4
 
"Eclipse Public License v1.0" which accompanies this distribution,
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     5
 
and is available at the URL "http://www.eclipse.org/legal/epl-v10.html". -->
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     6
 
<!-- Initial Contributors:
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     7
 
    Nokia Corporation - initial contribution.
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     8
 
Contributors:
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
     9
 
-->
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    10
 
<!DOCTYPE concept
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    11
 
  PUBLIC "-//OASIS//DTD DITA Concept//EN" "concept.dtd">
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    12
 
<concept id="GUID-FBE6E61F-5A2E-5A7A-BC59-51F072EBED7D" xml:lang="en"><title>Media
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    13
 
Driver Migration Guide</title><shortdesc>Describes the issues that need to be considered, when migrating
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    14
 
media drivers to a writable data demand paging environment. </shortdesc><prolog><metadata><keywords/></metadata></prolog><conbody>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    15
 
<section id="GUID-AB10DA2D-B7CC-47FD-B68A-1610B6BEAAE6"><title>Purpose</title> <p>This
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    16
 
document explains the points that have to be considered when migrating existing
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    17
 
media drivers to a writable data paging environment. </p>  </section>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    18
 
<section id="GUID-EB26A48A-3A34-44E8-9651-C7ED658CED51"><title>Issues Involved</title> <p>The
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    19
 
two main issues that have to be addressed when migrating existing media drivers
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    20
 
are: </p> <ul>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    21
 
<li id="GUID-68A44C67-6D4E-5D7E-A13B-0A82154073B2"><p>A deadlock condition
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    22
 
can occur between the driver and the client process, where both are trying
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    23
 
to access the same page of paged memory</p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    24
 
<li><p>A deadlock condition can occur between the driver and the client process,
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    25
 
where the client is allocating on the kernel heap, the paging system tries
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    26
 
to page out some data and the media driver also tries to allocate on the kernel
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    27
 
heap while servicing the resulting request.</p></li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    28
 
<li id="GUID-56A3815D-E07B-5195-85C3-0B93C08745C3"><p>Unpredictable delays
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    29
 
in servicing a DFC can occur, since memory might need to be paged in.</p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    30
 
</ul> <p>To address the above issues, the following points will have to be
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    31
 
considered/undertaken: </p> <ul>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    32
 
<li id="GUID-A15DB387-AB22-51BB-A4AD-0353932B788C"><p>Pass data by value to
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    33
 
DoRequest/DoControl </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    34
 
<li id="GUID-0FB5B141-94FE-54E4-9915-2DD50F840879"><p>Return results by using
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    35
 
a return code </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    36
 
<li id="GUID-9B3D3D25-010E-58C3-9C48-13AF494C3E62"><p>Use of a dedicated DFC
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    37
 
queue </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    38
 
<li id="GUID-AADA0BD7-75E7-5A11-98EB-F7EF3E1B5139"><p>Determine if unpredictable
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    39
 
delays in servicing DFCs are acceptable </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    40
 
<li id="GUID-E5B45EC9-DF21-51A9-814C-17CF3C13DFAE"><p>Validate the arguments
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    41
 
in the client context as far as possible </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    42
 
<li id="GUID-E6E4F7E2-1BE4-5590-AB05-777637C9B32B"><p>Move user memory accesses
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    43
 
to client context where possible </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    44
 
<li id="GUID-F4B44B27-9AE6-5A8C-B88C-C1809DAF6B89"><p>Replace the use of small
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    45
 
fixed-size structures with the use of the TClientDataRequest object </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    46
 
<li id="GUID-990D43F2-21C3-5C55-AC13-89C7153EA83B"><p>Pin user memory accessed
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    47
 
from DFCs </p><p>Do not allocate on the kernel heap while handling page out
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    48
 
requests.</p> <p>The paging algorithm can be over ridden and pages of memory
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    49
 
can be kept in memory (pinned). This situation can be reversed by 'unpinning'
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    50
 
the page. The TClientBufferRequest API provides this functionality. </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    51
 
<li id="GUID-67DB522A-DEB2-5FEA-ACA4-D80D09D80926"><p>Re-write the driver
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    52
 
to use shared chunks </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    53
 
<li id="GUID-A298C045-2260-55B5-89B9-595E3AF5472F"><p>No fast mutex may be
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    54
 
held when calling APIs that access user memory </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    55
 
<li id="GUID-F9F79078-0CBC-5E8F-899F-117D148C605A"><p>No kernel mutex may
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    56
 
be held </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    57
 
<li id="GUID-D378D276-CAF0-5B8B-BDA2-4D18EB87F96A"><p>Use the new APIs, (See
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    58
 
the <xref href="GUID-592B6D20-4ABA-5C79-9734-D18E2CE4A86C.dita">Writable Data Paging
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    59
 
Overview</xref> ). </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    60
 
</ul> </section>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    61
 
<section id="GUID-32E564F3-D66A-472B-A3C1-D2D61807A5F2"><title>See
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    62
 
also</title> <ul>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    63
 
<li id="GUID-77417650-C1F4-5ABC-9E75-54D274556FCD"><p> <xref href="GUID-E7C55048-5B7A-5BF2-B7F4-4D731659B88C.dita">Device
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    64
 
Driver Writing and Migration Guide</xref>  </p> <p>This document explains
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    65
 
techniques for writing device drivers on data paged systems and migrating
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    66
 
device drivers to data paged systems. </p> </li>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    67
 
</ul> </section>
307f4279f433 Initial contribution of the Adaptation Documentation.
Graeme Price <GRAEME.PRICE@NOKIA.COM>
parents:
diff changeset 
    68
 
</conbody></concept>
MCL/sftools/depl/docscontent