1<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> 2<html lang="en"> 3<head> 4 <meta http-equiv="content-type" content="text/html; charset=utf-8"> 5 <title>Submitting patches</title> 6 <link rel="stylesheet" type="text/css" href="mesa.css"> 7</head> 8<body> 9 10<div class="header"> 11 <h1>The Mesa 3D Graphics Library</h1> 12</div> 13 14<iframe src="contents.html"></iframe> 15<div class="content"> 16 17<h1>Submitting patches</h1> 18 19 20<ul> 21<li><a href="#guidelines">Basic guidelines</a> 22<li><a href="#formatting">Patch formatting</a> 23<li><a href="#testing">Testing Patches</a> 24<li><a href="#mailing">Mailing Patches</a> 25<li><a href="#reviewing">Reviewing Patches</a> 26<li><a href="#nominations">Nominating a commit for a stable branch</a> 27<li><a href="#criteria">Criteria for accepting patches to the stable branch</a> 28<li><a href="#gittips">Git tips</a> 29</ul> 30 31<h2 id="guidelines">Basic guidelines</h2> 32 33<ul> 34<li>Patches should not mix code changes with code formatting changes (except, 35perhaps, in very trivial cases.) 36<li>Code patches should follow Mesa 37<a href="codingstyle.html" target="_parent">coding conventions</a>. 38<li>Whenever possible, patches should only effect individual Mesa/Gallium 39components. 40<li>Patches should never introduce build breaks and should be bisectable (see 41<code>git bisect</code>.) 42<li>Patches should be properly <a href="#formatting">formatted</a>. 43<li>Patches should be sufficiently <a href="#testing">tested</a> before submitting. 44<li>Patches should be submitted to <a href="#mailing">mesa-dev</a> 45for <a href="#reviewing">review</a> using <code>git send-email</code>. 46 47</ul> 48 49<h2 id="formatting">Patch formatting</h2> 50 51<ul> 52<li>Lines should be limited to 75 characters or less so that git logs 53displayed in 80-column terminals avoid line wrapping. Note that git 54log uses 4 spaces of indentation (4 + 75 < 80). 55<li>The first line should be a short, concise summary of the change prefixed 56with a module name. Examples: 57<pre> 58 mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG 59 60 gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY 61 62 i965: Fix missing type in local variable declaration. 63</pre> 64<li>Subsequent patch comments should describe the change in more detail, 65if needed. For example: 66<pre> 67 i965: Remove end-of-thread SEND alignment code. 68 69 This was present in Eric's initial implementation of the compaction code 70 for Sandybridge (commit 077d01b6). There is no documentation saying this 71 is necessary, and removing it causes no regressions in piglit on any 72 platform. 73</pre> 74<li>A "Signed-off-by:" line is not required, but not discouraged either. 75<li>If a patch address a bugzilla issue, that should be noted in the 76patch comment. For example: 77<pre> 78 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=89689 79</pre> 80<li>If there have been several revisions to a patch during the review 81process, they should be noted such as in this example: 82<pre> 83 st/mesa: add ARB_texture_stencil8 support (v4) 84 85 if we support stencil texturing, enable texture_stencil8 86 there is no requirement to support native S8 for this, 87 the texture can be converted to x24s8 fine. 88 89 v2: fold fixes from Marek in: 90 a) put S8 last in the list 91 b) fix renderable to always test for d/s renderable 92 fixup the texture case to use a stencil only format 93 for picking the format for the texture view. 94 v3: hit fallback for getteximage 95 v4: put s8 back in front, it shouldn't get picked now (Ilia) 96</pre> 97<li>If someone tested your patch, document it with a line like this: 98<pre> 99 Tested-by: Joe Hacker <jhacker@foo.com> 100</pre> 101<li>If the patch was reviewed (usually the case) or acked by someone, 102that should be documented with: 103<pre> 104 Reviewed-by: Joe Hacker <jhacker@foo.com> 105 Acked-by: Joe Hacker <jhacker@foo.com> 106</pre> 107<li>If sending later revision of a patch, add all the tags - ack, r-b, 108Cc: mesa-stable and/or other. This provides reviewers with quick feedback if the 109patch has already been reviewed. 110<li>In order for your patch to reach the prospective reviewer easier/faster, 111use the script scripts/get_reviewer.pl to get a list of individuals and include 112them in the CC list. 113<br> 114Please use common sense and do <strong>not</strong> blindly add everyone. 115<br> 116<pre> 117 $ scripts/get_reviewer.pl --help # to get the the help screen 118 $ scripts/get_reviewer.pl -f src/egl/drivers/dri2/platform_android.c 119 Rob Herring <robh@kernel.org> (reviewer:ANDROID EGL SUPPORT,added_lines:188/700=27%,removed_lines:58/283=20%) 120 Tomasz Figa <tfiga@chromium.org> (reviewer:ANDROID EGL SUPPORT,authored:12/41=29%,added_lines:308/700=44%,removed_lines:115/283=41%) 121 Emil Velikov <emil.l.velikov@gmail.com> (authored:13/41=32%,removed_lines:76/283=27%) 122</pre> 123</ul> 124 125 126 127<h2 id="testing">Testing Patches</h2> 128 129<p> 130It should go without saying that patches must be tested. In general, 131do whatever testing is prudent. 132</p> 133 134<p> 135You should always run the Mesa test suite before submitting patches. 136The test suite can be run using the 'make check' command. All tests 137must pass before patches will be accepted, this may mean you have 138to update the tests themselves. 139</p> 140 141<p> 142Whenever possible and applicable, test the patch with 143<a href="http://piglit.freedesktop.org">Piglit</a> and/or 144<a href="https://android.googlesource.com/platform/external/deqp/">dEQP</a> 145to check for regressions. 146</p> 147 148 149<h2 id="mailing">Mailing Patches</h2> 150 151<p> 152Patches should be sent to the mesa-dev mailing list for review: 153<a href="https://lists.freedesktop.org/mailman/listinfo/mesa-dev"> 154mesa-dev@lists.freedesktop.org</a>. 155When submitting a patch make sure to use 156<a href="https://git-scm.com/docs/git-send-email">git send-email</a> 157rather than attaching patches to emails. Sending patches as 158attachments prevents people from being able to provide in-line review 159comments. 160</p> 161 162<p> 163When submitting follow-up patches you can use --in-reply-to to make v2, v3, 164etc patches show up as replies to the originals. This usually works well 165when you're sending out updates to individual patches (as opposed to 166re-sending the whole series). Using --in-reply-to makes 167it harder for reviewers to accidentally review old patches. 168</p> 169 170<p> 171When submitting follow-up patches you should also login to 172<a href="https://patchwork.freedesktop.org">patchwork</a> and change the 173state of your old patches to Superseded. 174</p> 175 176<h2 id="reviewing">Reviewing Patches</h2> 177 178<p> 179When you've reviewed a patch on the mailing list, please be unambiguous 180about your review. That is, state either 181</p> 182<pre> 183 Reviewed-by: Joe Hacker <jhacker@foo.com> 184</pre> 185or 186<pre> 187 Acked-by: Joe Hacker <jhacker@foo.com> 188</pre> 189<p> 190Rather than saying just "LGTM" or "Seems OK". 191</p> 192 193<p> 194If small changes are suggested, it's OK to say something like: 195</p> 196<pre> 197 With the above fixes, Reviewed-by: Joe Hacker <jhacker@foo.com> 198</pre> 199<p> 200which tells the patch author that the patch can be committed, as long 201as the issues are resolved first. 202</p> 203 204 205<h2 id="nominations">Nominating a commit for a stable branch</h2> 206 207<p> 208There are three ways to nominate patch for inclusion of the stable branch and 209release. 210</p> 211<ul> 212<li> By adding the Cc: mesa-stable@ tag as described below. 213<li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list. 214<li> Forwarding the patch from the mesa-dev@ mailing list. 215</li> 216</ul> 217<p> 218Note: resending patch identical to one on mesa-dev@ or one that differs only 219by the extra mesa-stable@ tag is <strong>not</strong> recommended. 220</p> 221 222 223<h3 id="thetag">The stable tag</h3> 224 225<p> 226If you want a commit to be applied to a stable branch, 227you should add an appropriate note to the commit message. 228</p> 229 230<p> 231Here are some examples of such a note: 232</p> 233<ul> 234 <li>CC: <mesa-stable@lists.freedesktop.org></li> 235 <li>CC: "9.2 10.0" <mesa-stable@lists.freedesktop.org></li> 236 <li>CC: "10.0" <mesa-stable@lists.freedesktop.org></li> 237</ul> 238 239Simply adding the CC to the mesa-stable list address is adequate to nominate 240the commit for the most-recently-created stable branch. It is only necessary 241to specify a specific branch name, (such as "9.2 10.0" or "10.0" in the 242examples above), if you want to nominate the commit for an older stable 243branch. And, as in these examples, you can nominate the commit for the older 244branch in addition to the more recent branch, or nominate the commit 245exclusively for the older branch. 246 247This "CC" syntax for patch nomination will cause patches to automatically be 248copied to the mesa-stable@ mailing list when you use "git send-email" to send 249patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that 250won't have any effect negative effect on the patch nomination. 251 252<p> 253Note: by removing the tag [as the commit is pushed] the patch is 254<strong>explicitly</strong> rejected from inclusion in the stable branch(es). 255<br> 256Thus, drop the line <strong>only</strong> if you want to cancel the nomination. 257</p> 258 259<h2 id="criteria">Criteria for accepting patches to the stable branch</h2> 260 261Mesa has a designated release manager for each stable branch, and the release 262manager is the only developer that should be pushing changes to these 263branches. Everyone else should simply nominate patches using the mechanism 264described above. 265 266The stable-release manager will work with the list of nominated patches, and 267for each patch that meets the criteria below will cherry-pick the patch with: 268<code>git cherry-pick -x <commit></code>. The <code>-x</code> option is 269important so that the picked patch references the commit ID of the original 270patch. 271 272The stable-release manager may at times need to force-push changes to the 273stable branches, for example, to drop a previously-picked patch that was later 274identified as causing a regression). These force-pushes may cause changes to 275be lost from the stable branch if developers push things directly. Consider 276yourself warned. 277 278The stable-release manager is also given broad discretion in rejecting patches 279that have been nominated for the stable branch. The most basic rule is that 280the stable branch is for bug fixes only, (no new features, no 281regressions). Here is a non-exhaustive list of some reasons that a patch may 282be rejected: 283 284<ul> 285 <li>Patch introduces a regression. Any reported build breakage or other 286 regression caused by a particular patch, (game no longer work, piglit test 287 changes from PASS to FAIL), is justification for rejecting a patch.</li> 288 289 <li>Patch is too large, (say, larger than 100 lines)</li> 290 291 <li>Patch is not a fix. For example, a commit that moves code around with no 292 functional change should be rejected.</li> 293 294 <li>Patch fix is not clearly described. For example, a commit message 295 of only a single line, no description of the bug, no mention of bugzilla, 296 etc.</li> 297 298 <li>Patch has not obviously been reviewed, For example, the commit message 299 has no Reviewed-by, Signed-off-by, nor Tested-by tags from anyone but the 300 author.</li> 301 302 <li>Patch has not already been merged to the master branch. As a rule, bug 303 fixes should never be applied first to a stable branch. Patches should land 304 first on the master branch and then be cherry-picked to a stable 305 branch. (This is to avoid future releases causing regressions if the patch 306 is not also applied to master.) The only things that might look like 307 exceptions would be backports of patches from master that happen to look 308 significantly different.</li> 309 310 <li>Patch depends on too many other patches. Ideally, all stable-branch 311 patches should be self-contained. It sometimes occurs that a single, logical 312 bug-fix occurs as two separate patches on master, (such as an original 313 patch, then a subsequent fix-up to that patch). In such a case, these two 314 patches should be squashed into a single, self-contained patch for the 315 stable branch. (Of course, if the squashing makes the patch too large, then 316 that could be a reason to reject the patch.)</li> 317 318 <li>Patch includes new feature development, not bug fixes. New OpenGL 319 features, extensions, etc. should be applied to Mesa master and included in 320 the next major release. Stable releases are intended only for bug fixes. 321 322 Note: As an exception to this rule, the stable-release manager may accept 323 hardware-enabling "features". For example, backports of new code to support 324 a newly-developed hardware product can be accepted if they can be reasonably 325 determined to not have effects on other hardware.</li> 326 327 <li>Patch is a performance optimization. As a rule, performance patches are 328 not candidates for the stable branch. The only exception might be a case 329 where an application's performance was recently severely impacted so as to 330 become unusable. The fix for this performance regression could then be 331 considered for a stable branch. The optimization must also be 332 non-controversial and the patches still need to meet the other criteria of 333 being simple and self-contained</li> 334 335 <li>Patch introduces a new failure mode (such as an assert). While the new 336 assert might technically be correct, for example to make Mesa more 337 conformant, this is not the kind of "bug fix" we want in a stable 338 release. The potential problem here is that an OpenGL program that was 339 previously working, (even if technically non-compliant with the 340 specification), could stop working after this patch. So that would be a 341 regression that is unacceptable for the stable branch.</li> 342</ul> 343 344<h2 id="gittips">Git tips</h2> 345 346<ul> 347<li><code>git rebase -i ...</code> is your friend. Don't be afraid to use it. 348<li>Apply a fixup to commit FOO. 349<pre> 350 git add ... 351 git commit --fixup=FOO 352 git rebase -i --autosquash ... 353</pre> 354<li>Test for build breakage between patches e.g last 8 commits. 355<pre> 356 git rebase -i --exec="make -j4" HEAD~8 357</pre> 358<li>Sets the default mailing address for your repo. 359<pre> 360 git config --local sendemail.to mesa-dev@lists.freedesktop.org 361</pre> 362<li> Add version to subject line of patch series in this case for the last 8 363commits before sending. 364<pre> 365 git send-email --subject-prefix="PATCH v4" HEAD~8 366 git send-email -v4 @~8 # shorter version, inherited from git format-patch 367</pre> 368<li> Configure git to use the get_reviewer.pl script interactively. Thus you 369can avoid adding the world to the CC list. 370<pre> 371 git config sendemail.cccmd "./scripts/get_reviewer.pl -i" 372</pre> 373</ul> 374 375 376</div> 377</body> 378</html> 379