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author | Scott Rifenbark <scott.m.rifenbark@intel.com> | 2010-12-03 07:32:13 -0800 |
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committer | Saul Wold <Saul.Wold@intel.com> | 2010-12-10 22:01:27 -0800 |
commit | 579b5c2947c57eef3bc379272ceec6f95f980736 (patch) | |
tree | 7ce1b81592d081ee41a77d8d022e674350e4e90d /documentation/kernel-manual/kernel-concepts.xml | |
parent | 9f4c630dbd1ba074e20b69b759404ef31595851d (diff) | |
download | poky-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.xml | 28 |
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. |