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11 The Mesa
3D Graphics Library
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17 <h1>Submitting Patches
</h1>
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=
"#submit">Submitting 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=
"#backports">Sending backports for the stable branch
</a>
29 <li><a href=
"#gittips">Git tips
</a>
32 <h2 id=
"guidelines">Basic guidelines
</h2>
35 <li>Patches should not mix code changes with code formatting changes (except,
36 perhaps, in very trivial cases.)
37 <li>Code patches should follow Mesa
38 <a href=
"codingstyle.html" target=
"_parent">coding conventions
</a>.
39 <li>Whenever possible, patches should only affect individual Mesa/Gallium
41 <li>Patches should never introduce build breaks and should be bisectable (see
42 <code>git bisect
</code>.)
43 <li>Patches should be properly
<a href=
"#formatting">formatted
</a>.
44 <li>Patches should be sufficiently
<a href=
"#testing">tested
</a> before submitting.
45 <li>Patches should be
<a href=
"#submit">submitted
</a>
46 to
<a href=
"#mailing">mesa-dev
</a> or with
47 a
<a href=
"#merge-request">merge request
</a>
48 for
<a href=
"#reviewing">review
</a>.
52 <h2 id=
"formatting">Patch formatting
</h2>
55 <li>Lines should be limited to
75 characters or less so that git logs
56 displayed in
80-column terminals avoid line wrapping. Note that git
57 log uses
4 spaces of indentation (
4 +
75 < 80).
58 <li>The first line should be a short, concise summary of the change prefixed
59 with a module name. Examples:
61 mesa: Add support for querying GL_VERTEX_ATTRIB_ARRAY_LONG
63 gallium: add PIPE_CAP_DEVICE_RESET_STATUS_QUERY
65 i965: Fix missing type in local variable declaration.
67 <li>Subsequent patch comments should describe the change in more detail,
68 if needed. For example:
70 i965: Remove end-of-thread SEND alignment code.
72 This was present in Eric's initial implementation of the compaction code
73 for Sandybridge (commit
077d01b6). There is no documentation saying this
74 is necessary, and removing it causes no regressions in piglit on any
77 <li>A
"Signed-off-by:" line is not required, but not discouraged either.
78 <li>If a patch addresses an issue in gitlab, use the Closes: tag
81 Closes: https://gitlab.freedesktop.org/mesa/mesa/issues/
1
83 <p>Prefer the full url to just
<pre>Closes: #
1</pre>, since the url makes it
84 easier to get to the bug page from
<pre>git log
</pre></p>
85 <b>Do not use the Fixes: tag for this!
</b> Mesa already uses Fixes for something else.
87 <li>If a patch addresses a issue introduced with earlier commit, that should be
88 noted in the patch comment. For example:
90 Fixes: d7b3707c612
"util/disk_cache: use stat() to check if entry is a directory"
92 <li>You can produce those fixes lines by running
93 <pre>git config --global alias.fixes
"show -s --pretty='format:Fixes: %h (\"%s\
")'"</pre>
94 once and then using
<pre>git fixes
<sha1
></pre>
95 <li>If there have been several revisions to a patch during the review
96 process, they should be noted such as in this example:
98 st/mesa: add ARB_texture_stencil8 support (v4)
100 if we support stencil texturing, enable texture_stencil8
101 there is no requirement to support native S8 for this,
102 the texture can be converted to x24s8 fine.
104 v2: fold fixes from Marek in:
105 a) put S8 last in the list
106 b) fix renderable to always test for d/s renderable
107 fixup the texture case to use a stencil only format
108 for picking the format for the texture view.
109 v3: hit fallback for getteximage
110 v4: put s8 back in front, it shouldn't get picked now (Ilia)
112 <li>If someone tested your patch, document it with a line like this:
114 Tested-by: Joe Hacker
<jhacker@foo.com
>
116 <li>If the patch was reviewed (usually the case) or acked by someone,
117 that should be documented with:
119 Reviewed-by: Joe Hacker
<jhacker@foo.com
>
120 Acked-by: Joe Hacker
<jhacker@foo.com
>
122 <li>If sending later revision of a patch, add all the tags - ack, r-b,
123 Cc: mesa-stable and/or other. This provides reviewers with quick feedback if the
124 patch has already been reviewed.
129 <h2 id=
"testing">Testing Patches
</h2>
132 It should go without saying that patches must be tested. In general,
133 do whatever testing is prudent.
137 You should always run the Mesa test suite before submitting patches.
138 The test suite can be run using the 'meson test' command. All tests
139 must pass before patches will be accepted, this may mean you have
140 to update the tests themselves.
144 Whenever possible and applicable, test the patch with
145 <a href=
"https://piglit.freedesktop.org">Piglit
</a> and/or
146 <a href=
"https://android.googlesource.com/platform/external/deqp/">dEQP
</a>
147 to check for regressions.
151 As mentioned at the begining, patches should be bisectable.
152 A good way to test this is to make use of the `git rebase` command,
153 to run your tests on each commit. Assuming your branch is based off
154 <code>origin/master
</code>, you can run:
157 $ git rebase --interactive --exec
"meson test -C build/" origin/master
160 replacing
<code>"meson test"</code> with whatever other test you want to
165 <h2 id=
"submit">Submitting Patches
</h2>
168 Patches may be submitted to the Mesa project by
169 <a href=
"#mailing">email
</a> or with a
170 GitLab
<a href=
"#merge-request">merge request
</a>. To prevent
171 duplicate code review, only use one method to submit your changes.
174 <h3 id=
"mailing">Mailing Patches
</h3>
177 Patches may be sent to the mesa-dev mailing list for review:
178 <a href=
"https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
179 mesa-dev@lists.freedesktop.org
</a>.
180 When submitting a patch make sure to use
181 <a href=
"https://git-scm.com/docs/git-send-email">git send-email
</a>
182 rather than attaching patches to emails. Sending patches as
183 attachments prevents people from being able to provide in-line review
188 When submitting follow-up patches you can use --in-reply-to to make v2, v3,
189 etc patches show up as replies to the originals. This usually works well
190 when you're sending out updates to individual patches (as opposed to
191 re-sending the whole series). Using --in-reply-to makes
192 it harder for reviewers to accidentally review old patches.
196 When submitting follow-up patches you should also login to
197 <a href=
"https://patchwork.freedesktop.org">patchwork
</a> and change the
198 state of your old patches to Superseded.
202 Some companies' mail server automatically append a legal disclaimer,
203 usually containing something along the lines of
"The information in this
204 email is confidential" and
"distribution is strictly prohibited".
207 These legal notices prevent us from being able to accept your patch,
208 rendering the whole process pointless. Please make sure these are
209 disabled before sending your patches. (Note that you may need to contact
210 your email administrator for this.)
213 <h3 id=
"merge-request">GitLab Merge Requests
</h3>
216 <a href=
"https://gitlab.freedesktop.org/mesa/mesa">GitLab
</a> Merge
217 Requests (MR) can also be used to submit patches for Mesa.
221 If the MR may have interest for most of the Mesa community, you can
222 send an email to the mesa-dev email list including a link to the MR.
223 Don't send the patch to mesa-dev, just the MR link.
226 Add labels to your MR to help reviewers find it. For example:
229 <li>Mesa changes affecting all drivers: mesa
230 <li>Hardware vendor specific code: amd, intel, nvidia, ...
231 <li>Driver specific code: anvil, freedreno, i965, iris, radeonsi,
233 <li>Other tag examples: gallium, util
236 Tick the following when creating the MR. It allows developers to
237 rebase your work on top of master.
239 <pre>Allow commits from members who can merge to the target branch
</pre>
241 If you revise your patches based on code review and push an update
242 to your branch, you should maintain a
<strong>clean
</strong> history
243 in your patches. There should not be
"fixup" patches in the history.
244 The series should be buildable and functional after every commit
245 whenever you push the branch.
248 It is your responsibility to keep the MR alive and making progress,
249 as there are no guarantees that a Mesa dev will independently take
256 <li>Make changes and update your branch based on feedback
257 <li>After an update, for the feedback you handled, close the
258 feedback discussion with the
"Resolve Discussion" button. This way
259 the reviewers know which feedback got handled and which didn't.
260 <li>Old, stale MR may be closed, but you can reopen it if you
261 still want to pursue the changes
262 <li>You should periodically check to see if your MR needs to be
264 <li>Make sure your MR is closed if your patches get pushed outside
266 <li>Please send MRs from a personal fork rather than from the main
267 Mesa repository, as it clutters it unnecessarily.
270 <h2 id=
"reviewing">Reviewing Patches
</h2>
273 To participate in code review, you should monitor the
274 <a href=
"https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
275 mesa-dev
</a> email list and the GitLab
276 Mesa
<a href=
"https://gitlab.freedesktop.org/mesa/mesa/merge_requests">Merge
281 When you've reviewed a patch on the mailing list, please be unambiguous
282 about your review. That is, state either
285 Reviewed-by: Joe Hacker
<jhacker@foo.com
>
289 Acked-by: Joe Hacker
<jhacker@foo.com
>
292 Rather than saying just
"LGTM" or
"Seems OK".
296 If small changes are suggested, it's OK to say something like:
299 With the above fixes, Reviewed-by: Joe Hacker
<jhacker@foo.com
>
302 which tells the patch author that the patch can be committed, as long
303 as the issues are resolved first.
307 These Reviewed-by, Acked-by, and Tested-by tags should also be amended
308 into commits in a MR before it is merged.
312 When providing a Reviewed-by, Acked-by, or Tested-by tag in a gitlab MR,
313 enclose the tag in backticks:
316 `Reviewed-by: Joe Hacker
<jhacker@example.com
>`
</pre>
318 This is the markdown format for literal, and will prevent gitlab from hiding
319 the
< and
> symbols.
323 Review by non-experts is encouraged. Understanding how someone else
324 goes about solving a problem is a great way to learn your way around
325 the project. The submitter is expected to evaluate whether they have
326 an appropriate amount of review feedback from people who also
327 understand the code before merging their patches.
330 <h2 id=
"nominations">Nominating a commit for a stable branch
</h2>
333 There are three ways to nominate a patch for inclusion in the stable branch and
337 <li> By adding the Cc: mesa-stable@ tag as described below.
338 <li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list.
339 <li> Forwarding the patch from the mesa-dev@ mailing list.
343 Note: resending patch identical to one on mesa-dev@ or one that differs only
344 by the extra mesa-stable@ tag is
<strong>not
</strong> recommended.
347 If you are not the author of the original patch, please Cc: them in your
352 The current patch status can be observed in the
<a href=
"releasing.html#stagingbranch">staging branch
</a>.
355 <h3 id=
"thetag">The stable tag
</h3>
358 If you want a commit to be applied to a stable branch,
359 you should add an appropriate note to the commit message.
363 Here are some examples of such a note:
366 CC:
<mesa-stable@lists.freedesktop.org
>
369 Simply adding the CC to the mesa-stable list address is adequate to nominate
370 the commit for all the active stable branches. If the commit is not applicable
371 for said branch the stable-release manager will reply stating so.
373 This
"CC" syntax for patch nomination will cause patches to automatically be
374 copied to the mesa-stable@ mailing list when you use
"git send-email" to send
375 patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that
376 won't have any negative effect on the patch nomination.
379 Note: by removing the tag [as the commit is pushed] the patch is
380 <strong>explicitly
</strong> rejected from inclusion in the stable branch(es).
381 Thus, drop the line
<strong>only
</strong> if you want to cancel the nomination.
384 Alternatively, if one uses the
"Fixes" tag as described in the
"Patch formatting"
385 section, it nominates a commit for all active stable branches that include the
386 commit that is referred to.
388 <h2 id=
"criteria">Criteria for accepting patches to the stable branch
</h2>
390 Mesa has a designated release manager for each stable branch, and the release
391 manager is the only developer that should be pushing changes to these branches.
392 Everyone else should nominate patches using the mechanism described above.
394 The following rules define which patches are accepted and which are not. The
395 stable-release manager is also given broad discretion in rejecting patches
396 that have been nominated.
399 <li>Patch must conform with the
<a href=
"#guidelines">Basic guidelines
</a></li>
401 <li>Patch must have landed in master first. In case where the original
402 patch is too large and/or otherwise contradicts with the rules set within, a
403 backport is appropriate.
</li>
405 <li>It must not introduce a regression - be that build or runtime wise.
407 Note: If the regression is due to faulty piglit/dEQP/CTS/other test the
408 latter must be fixed first. A reference to the offending test(s) and
409 respective fix(es) should be provided in the nominated patch.
</li>
411 <li>Patch cannot be larger than
100 lines.
</li>
413 <li>Patches that move code around with no functional change should be
416 <li>Patch must be a bug fix and not a new feature.
418 Note: An exception to this rule, are hardware-enabling
"features". For
419 example,
<a href=
"#backports">backports
</a> of new code to support a
420 newly-developed hardware product can be accepted if they can be reasonably
421 determined not to have effects on other hardware.
</li>
423 <li>Patch must be reviewed, For example, the commit message has Reviewed-by,
424 Signed-off-by, or Tested-by tags from someone but the author.
</li>
426 <li>Performance patches are considered only if they provide information
427 about the hardware, program in question and observed improvement. Use numbers
428 to represent your measurements.
</li>
431 If the patch complies with the rules it will be
432 <a href=
"releasing.html#pickntest">cherry-picked
</a>. Alternatively the release
433 manager will reply to the patch in question stating why the patch has been
434 rejected or would request a backport.
436 A summary of all the picked/rejected patches will be presented in the
437 <a href=
"releasing.html#prerelease">pre-release
</a> announcement.
439 The stable-release manager may at times need to force-push changes to the
440 stable branches, for example, to drop a previously-picked patch that was later
441 identified as causing a regression). These force-pushes may cause changes to
442 be lost from the stable branch if developers push things directly. Consider
445 <h2 id=
"backports">Sending backports for the stable branch
</h2>
447 By default merge conflicts are resolved by the stable-release manager. In which
448 case he/she should provide a comment about the changes required, alongside the
449 <code>Conflicts
</code> section. Summary of which will be provided in the
450 <a href=
"releasing.html#prerelease">pre-release
</a> announcement.
454 Developers are interested in sending backports are recommended to use either a
455 <code>[BACKPORT #branch]
</code> subject prefix or provides similar information
456 within the commit summary.
459 <h2 id=
"gittips">Git tips
</h2>
462 <li><code>git rebase -i ...
</code> is your friend. Don't be afraid to use it.
463 <li>Apply a fixup to commit FOO.
466 git commit --fixup=FOO
467 git rebase -i --autosquash ...
469 <li>Test for build breakage between patches e.g last
8 commits.
471 git rebase -i
--exec=
"ninja -C build/" HEAD~
8
473 <li>Sets the default mailing address for your repo.
475 git config --local sendemail.to mesa-dev@lists.freedesktop.org
477 <li> Add version to subject line of patch series in this case for the last
8
478 commits before sending.
480 git send-email
--subject-prefix=
"PATCH v4" HEAD~
8
481 git send-email -v4 @~
8 # shorter version, inherited from git format-patch