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authorScott Rifenbark <scott.m.rifenbark@intel.com>2010-12-03 07:32:13 -0800
committerSaul Wold <Saul.Wold@intel.com>2010-12-10 22:01:27 -0800
commit579b5c2947c57eef3bc379272ceec6f95f980736 (patch)
tree7ce1b81592d081ee41a77d8d022e674350e4e90d /documentation/kernel-manual/kernel-concepts.xml
parent9f4c630dbd1ba074e20b69b759404ef31595851d (diff)
downloadpoky-579b5c2947c57eef3bc379272ceec6f95f980736.tar.gz
documentation/kernel-manual: Added Bruce Ashfields review comments.
Comments covered some minor points. We did remove the "Creating a Transition Kernel Layer" section however. Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Diffstat (limited to 'documentation/kernel-manual/kernel-concepts.xml')
-rw-r--r--documentation/kernel-manual/kernel-concepts.xml28
1 files changed, 18 insertions, 10 deletions
diff --git a/documentation/kernel-manual/kernel-concepts.xml b/documentation/kernel-manual/kernel-concepts.xml
index 872264c846..d2ebab0101 100644
--- a/documentation/kernel-manual/kernel-concepts.xml
+++ b/documentation/kernel-manual/kernel-concepts.xml
@@ -43,7 +43,7 @@
43 <listitem><para>Provide mechanisms that support many different work flows, front-ends and 43 <listitem><para>Provide mechanisms that support many different work flows, front-ends and
44 management techniques.</para></listitem> 44 management techniques.</para></listitem>
45 <listitem><para>Deliver the most up-to-date kernel possible while still ensuring that 45 <listitem><para>Deliver the most up-to-date kernel possible while still ensuring that
46 the baseline kernel is the the most stable official release.</para></listitem> 46 the baseline kernel is the most stable official release.</para></listitem>
47 <listitem><para>Include major technological features as part of Yocto Project's up-rev 47 <listitem><para>Include major technological features as part of Yocto Project's up-rev
48 strategy.</para></listitem> 48 strategy.</para></listitem>
49 <listitem><para>Present a git tree, that just like the upstream kernel.org tree, has a 49 <listitem><para>Present a git tree, that just like the upstream kernel.org tree, has a
@@ -80,9 +80,10 @@
80 <para> 80 <para>
81 The ultimate source for the Yocto Project kernel is a released kernel 81 The ultimate source for the Yocto Project kernel is a released kernel
82 from kernel.org. 82 from kernel.org.
83 In addition to a foundational kernel from kernel.org the commercially released 83 In addition to a foundational kernel from kernel.org the released
84 Yocto Project kernel contains a mix of important new mainline 84 Yocto Project kernel contains a mix of important new mainline
85 developments, non-mainline developments, Board Support Package (BSP) developments, 85 developments, non-mainline developments (when there is no alternative),
86 Board Support Package (BSP) developments,
86 and custom features. 87 and custom features.
87 These additions result in a commercially released Yocto Project kernel that caters 88 These additions result in a commercially released Yocto Project kernel that caters
88 to specific embedded designer needs for targeted hardware. 89 to specific embedded designer needs for targeted hardware.
@@ -105,7 +106,8 @@
105 </para> --> 106 </para> -->
106 <para> 107 <para>
107 Once a Yocto Project kernel is officially released the Yocto Project team goes into 108 Once a Yocto Project kernel is officially released the Yocto Project team goes into
108 their next development cycle, or "uprev" cycle. 109 their next development cycle, or "uprev" cycle while continuing maintenance on the
110 released kernel.
109 It is important to note that the most sustainable and stable way 111 It is important to note that the most sustainable and stable way
110 to include feature development upstream is through a kernel uprev process. 112 to include feature development upstream is through a kernel uprev process.
111 Back-porting of hundreds of individual fixes and minor features from various 113 Back-porting of hundreds of individual fixes and minor features from various
@@ -143,8 +145,8 @@
143 This kernel gives insight into new features and allows focused 145 This kernel gives insight into new features and allows focused
144 amounts of testing to be done on the kernel, which prevents 146 amounts of testing to be done on the kernel, which prevents
145 surprises when selecting the next major uprev. 147 surprises when selecting the next major uprev.
146 The quality of these cutting edge kernels is evolving and the kernels are used in very special 148 The quality of these cutting edge kernels is evolving and the kernels are used in leading edge
147 cases for BSP and feature development. 149 feature and BSP development.
148 </para> 150 </para>
149 </section> 151 </section>
150 152
@@ -199,7 +201,8 @@
199 Each branch represents some unique functionality for the BSP or a real-time kernel. 201 Each branch represents some unique functionality for the BSP or a real-time kernel.
200 </para> 202 </para>
201 <para> 203 <para>
202 The real-time kernel branch has common features for all real-time kernels and contains 204 In this example structure, the real-time kernel branch has common features for all
205 real-time kernels and contains
203 more branches for individual BSP-specific real-time kernels. 206 more branches for individual BSP-specific real-time kernels.
204 The illustration shows three branches as an example. 207 The illustration shows three branches as an example.
205 Each branch points the way to specific, unique features for a respective real-time 208 Each branch points the way to specific, unique features for a respective real-time
@@ -226,6 +229,11 @@
226 Rather we store the unique differences required to apply the feature onto the kernel type 229 Rather we store the unique differences required to apply the feature onto the kernel type
227 in question. 230 in question.
228 </para> 231 </para>
232 <note><para>
233 This practice is not typically encouraged.
234 However, during development cycles or when large features are merged the practice
235 can't be avoided.
236 </para></note>
229 <para> 237 <para>
230 BSP-specific code additions are handled in a similar manner to kernel-specific additions. 238 BSP-specific code additions are handled in a similar manner to kernel-specific additions.
231 Some BSPs only make sense given certain kernel types. 239 Some BSPs only make sense given certain kernel types.
@@ -238,13 +246,13 @@
238 the supported multiple kernels are uniquely stored. 246 the supported multiple kernels are uniquely stored.
239 </para> 247 </para>
240 <para> 248 <para>
241 While this strategy results in a tree with a significant number of branches, it is 249 While this strategy can result in a tree with a significant number of branches, it is
242 important to realize that from the customer's point of view, there is a linear 250 important to realize that from the user's point of view, there is a linear
243 path that travels from the baseline kernel.org, through a select group of features and 251 path that travels from the baseline kernel.org, through a select group of features and
244 ends with their BSP-specific commits. 252 ends with their BSP-specific commits.
245 In other words, the divisions of the kernel are transparent and are not relevant 253 In other words, the divisions of the kernel are transparent and are not relevant
246 to the developer on a day-to-day basis. 254 to the developer on a day-to-day basis.
247 From the customer's perspective, this is the "master" branch. 255 From the user's perspective, this is the "master" branch.
248 They do not need not be aware of the existence of any other branches at all. 256 They do not need not be aware of the existence of any other branches at all.
249 Of course there is value in the existence of these branches 257 Of course there is value in the existence of these branches
250 in the tree, should a person decide to explore them. 258 in the tree, should a person decide to explore them.