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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 a bugzilla issue, that should be noted in the
79 patch comment. For example:
81 Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=
89689
83 <li>If a patch addresses a issue introduced with earlier commit, that should be
84 noted in the patch comment. For example:
86 Fixes: d7b3707c612
"util/disk_cache: use stat() to check if entry is a directory"
88 <li>If there have been several revisions to a patch during the review
89 process, they should be noted such as in this example:
91 st/mesa: add ARB_texture_stencil8 support (v4)
93 if we support stencil texturing, enable texture_stencil8
94 there is no requirement to support native S8 for this,
95 the texture can be converted to x24s8 fine.
97 v2: fold fixes from Marek in:
98 a) put S8 last in the list
99 b) fix renderable to always test for d/s renderable
100 fixup the texture case to use a stencil only format
101 for picking the format for the texture view.
102 v3: hit fallback for getteximage
103 v4: put s8 back in front, it shouldn't get picked now (Ilia)
105 <li>If someone tested your patch, document it with a line like this:
107 Tested-by: Joe Hacker
<jhacker@foo.com
>
109 <li>If the patch was reviewed (usually the case) or acked by someone,
110 that should be documented with:
112 Reviewed-by: Joe Hacker
<jhacker@foo.com
>
113 Acked-by: Joe Hacker
<jhacker@foo.com
>
115 <li>If sending later revision of a patch, add all the tags - ack, r-b,
116 Cc: mesa-stable and/or other. This provides reviewers with quick feedback if the
117 patch has already been reviewed.
118 <li>In order for your patch to reach the prospective reviewer easier/faster,
119 use the script scripts/get_reviewer.pl to get a list of individuals and include
122 Please use common sense and do
<strong>not
</strong> blindly add everyone.
125 $ scripts/get_reviewer.pl --help # to get the help screen
126 $ scripts/get_reviewer.pl -f src/egl/drivers/dri2/platform_android.c
127 Rob Herring
<robh@kernel.org
> (reviewer:ANDROID EGL SUPPORT,added_lines:
188/
700=
27%,removed_lines:
58/
283=
20%)
128 Tomasz Figa
<tfiga@chromium.org
> (reviewer:ANDROID EGL SUPPORT,authored:
12/
41=
29%,added_lines:
308/
700=
44%,removed_lines:
115/
283=
41%)
129 Emil Velikov
<emil.l.velikov@gmail.com
> (authored:
13/
41=
32%,removed_lines:
76/
283=
27%)
135 <h2 id=
"testing">Testing Patches
</h2>
138 It should go without saying that patches must be tested. In general,
139 do whatever testing is prudent.
143 You should always run the Mesa test suite before submitting patches.
144 The test suite can be run using the 'meson test' command. All tests
145 must pass before patches will be accepted, this may mean you have
146 to update the tests themselves.
150 Whenever possible and applicable, test the patch with
151 <a href=
"https://piglit.freedesktop.org">Piglit
</a> and/or
152 <a href=
"https://android.googlesource.com/platform/external/deqp/">dEQP
</a>
153 to check for regressions.
157 As mentioned at the begining, patches should be bisectable.
158 A good way to test this is to make use of the `git rebase` command,
159 to run your tests on each commit. Assuming your branch is based off
160 <code>origin/master
</code>, you can run:
163 $ git rebase --interactive --exec
"meson test -C build/" origin/master
166 replacing
<code>"meson test"</code> with whatever other test you want to
171 <h2 id=
"submit">Submitting Patches
</h2>
174 Patches may be submitted to the Mesa project by
175 <a href=
"#mailing">email
</a> or with a
176 GitLab
<a href=
"#merge-request">merge request
</a>. To prevent
177 duplicate code review, only use one method to submit your changes.
180 <h3 id=
"mailing">Mailing Patches
</h3>
183 Patches may be sent to the mesa-dev mailing list for review:
184 <a href=
"https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
185 mesa-dev@lists.freedesktop.org
</a>.
186 When submitting a patch make sure to use
187 <a href=
"https://git-scm.com/docs/git-send-email">git send-email
</a>
188 rather than attaching patches to emails. Sending patches as
189 attachments prevents people from being able to provide in-line review
194 When submitting follow-up patches you can use --in-reply-to to make v2, v3,
195 etc patches show up as replies to the originals. This usually works well
196 when you're sending out updates to individual patches (as opposed to
197 re-sending the whole series). Using --in-reply-to makes
198 it harder for reviewers to accidentally review old patches.
202 When submitting follow-up patches you should also login to
203 <a href=
"https://patchwork.freedesktop.org">patchwork
</a> and change the
204 state of your old patches to Superseded.
208 Some companies' mail server automatically append a legal disclaimer,
209 usually containing something along the lines of
"The information in this
210 email is confidential" and
"distribution is strictly prohibited".
213 These legal notices prevent us from being able to accept your patch,
214 rendering the whole process pointless. Please make sure these are
215 disabled before sending your patches. (Note that you may need to contact
216 your email administrator for this.)
219 <h3 id=
"merge-request">GitLab Merge Requests
</h3>
222 <a href=
"https://gitlab.freedesktop.org/mesa/mesa">GitLab
</a> Merge
223 Requests (MR) can also be used to submit patches for Mesa.
227 If the MR may have interest for most of the Mesa community, you can
228 send an email to the mesa-dev email list including a link to the MR.
229 Don't send the patch to mesa-dev, just the MR link.
232 Add labels to your MR to help reviewers find it. For example:
235 <li>Mesa changes affecting all drivers: mesa
236 <li>Hardware vendor specific code: amd, intel, nvidia, ...
237 <li>Driver specific code: anvil, freedreno, i965, iris, radeonsi,
239 <li>Other tag examples: gallium, util
242 Tick the following when creating the MR. It allows developers to
243 rebase your work on top of master.
245 <pre>Allow commits from members who can merge to the target branch
</pre>
247 If you revise your patches based on code review and push an update
248 to your branch, you should maintain a
<strong>clean
</strong> history
249 in your patches. There should not be
"fixup" patches in the history.
250 The series should be buildable and functional after every commit
251 whenever you push the branch.
254 It is your responsibility to keep the MR alive and making progress,
255 as there are no guarantees that a Mesa dev will independently take
262 <li>Make changes and update your branch based on feedback
263 <li>After an update, for the feedback you handled, close the
264 feedback discussion with the
"Resolve Discussion" button. This way
265 the reviewers know which feedback got handled and which didn't.
266 <li>Old, stale MR may be closed, but you can reopen it if you
267 still want to pursue the changes
268 <li>You should periodically check to see if your MR needs to be
270 <li>Make sure your MR is closed if your patches get pushed outside
272 <li>Please send MRs from a personal fork rather than from the main
273 Mesa repository, as it clutters it unnecessarily.
276 <h2 id=
"reviewing">Reviewing Patches
</h2>
279 To participate in code review, you should monitor the
280 <a href=
"https://lists.freedesktop.org/mailman/listinfo/mesa-dev">
281 mesa-dev
</a> email list and the GitLab
282 Mesa
<a href=
"https://gitlab.freedesktop.org/mesa/mesa/merge_requests">Merge
287 When you've reviewed a patch on the mailing list, please be unambiguous
288 about your review. That is, state either
291 Reviewed-by: Joe Hacker
<jhacker@foo.com
>
295 Acked-by: Joe Hacker
<jhacker@foo.com
>
298 Rather than saying just
"LGTM" or
"Seems OK".
302 If small changes are suggested, it's OK to say something like:
305 With the above fixes, Reviewed-by: Joe Hacker
<jhacker@foo.com
>
308 which tells the patch author that the patch can be committed, as long
309 as the issues are resolved first.
313 These Reviewed-by, Acked-by, and Tested-by tags should also be amended
314 into commits in a MR before it is merged.
318 When providing a Reviewed-by, Acked-by, or Tested-by tag in a gitlab MR,
319 enclose the tag in backticks:
322 `Reviewed-by: Joe Hacker
<jhacker@example.com
>`
</pre>
324 This is the markdown format for literal, and will prevent gitlab from hiding
325 the
< and
> symbols.
329 Review by non-experts is encouraged. Understanding how someone else
330 goes about solving a problem is a great way to learn your way around
331 the project. The submitter is expected to evaluate whether they have
332 an appropriate amount of review feedback from people who also
333 understand the code before merging their patches.
336 <h2 id=
"nominations">Nominating a commit for a stable branch
</h2>
339 There are three ways to nominate a patch for inclusion in the stable branch and
343 <li> By adding the Cc: mesa-stable@ tag as described below.
344 <li> Sending the commit ID (as seen in master branch) to the mesa-stable@ mailing list.
345 <li> Forwarding the patch from the mesa-dev@ mailing list.
349 Note: resending patch identical to one on mesa-dev@ or one that differs only
350 by the extra mesa-stable@ tag is
<strong>not
</strong> recommended.
353 If you are not the author of the original patch, please Cc: them in your
358 The current patch status can be observed in the
<a href=
"releasing.html#stagingbranch">staging branch
</a>.
361 <h3 id=
"thetag">The stable tag
</h3>
364 If you want a commit to be applied to a stable branch,
365 you should add an appropriate note to the commit message.
369 Here are some examples of such a note:
372 CC:
<mesa-stable@lists.freedesktop.org
>
375 Simply adding the CC to the mesa-stable list address is adequate to nominate
376 the commit for all the active stable branches. If the commit is not applicable
377 for said branch the stable-release manager will reply stating so.
379 This
"CC" syntax for patch nomination will cause patches to automatically be
380 copied to the mesa-stable@ mailing list when you use
"git send-email" to send
381 patches to the mesa-dev@ mailing list. If you prefer using --suppress-cc that
382 won't have any negative effect on the patch nomination.
385 Note: by removing the tag [as the commit is pushed] the patch is
386 <strong>explicitly
</strong> rejected from inclusion in the stable branch(es).
387 Thus, drop the line
<strong>only
</strong> if you want to cancel the nomination.
390 Alternatively, if one uses the
"Fixes" tag as described in the
"Patch formatting"
391 section, it nominates a commit for all active stable branches that include the
392 commit that is referred to.
394 <h2 id=
"criteria">Criteria for accepting patches to the stable branch
</h2>
396 Mesa has a designated release manager for each stable branch, and the release
397 manager is the only developer that should be pushing changes to these branches.
398 Everyone else should nominate patches using the mechanism described above.
400 The following rules define which patches are accepted and which are not. The
401 stable-release manager is also given broad discretion in rejecting patches
402 that have been nominated.
405 <li>Patch must conform with the
<a href=
"#guidelines">Basic guidelines
</a></li>
407 <li>Patch must have landed in master first. In case where the original
408 patch is too large and/or otherwise contradicts with the rules set within, a
409 backport is appropriate.
</li>
411 <li>It must not introduce a regression - be that build or runtime wise.
413 Note: If the regression is due to faulty piglit/dEQP/CTS/other test the
414 latter must be fixed first. A reference to the offending test(s) and
415 respective fix(es) should be provided in the nominated patch.
</li>
417 <li>Patch cannot be larger than
100 lines.
</li>
419 <li>Patches that move code around with no functional change should be
422 <li>Patch must be a bug fix and not a new feature.
424 Note: An exception to this rule, are hardware-enabling
"features". For
425 example,
<a href=
"#backports">backports
</a> of new code to support a
426 newly-developed hardware product can be accepted if they can be reasonably
427 determined not to have effects on other hardware.
</li>
429 <li>Patch must be reviewed, For example, the commit message has Reviewed-by,
430 Signed-off-by, or Tested-by tags from someone but the author.
</li>
432 <li>Performance patches are considered only if they provide information
433 about the hardware, program in question and observed improvement. Use numbers
434 to represent your measurements.
</li>
437 If the patch complies with the rules it will be
438 <a href=
"releasing.html#pickntest">cherry-picked
</a>. Alternatively the release
439 manager will reply to the patch in question stating why the patch has been
440 rejected or would request a backport.
442 A summary of all the picked/rejected patches will be presented in the
443 <a href=
"releasing.html#prerelease">pre-release
</a> announcement.
445 The stable-release manager may at times need to force-push changes to the
446 stable branches, for example, to drop a previously-picked patch that was later
447 identified as causing a regression). These force-pushes may cause changes to
448 be lost from the stable branch if developers push things directly. Consider
451 <h2 id=
"backports">Sending backports for the stable branch
</h2>
453 By default merge conflicts are resolved by the stable-release manager. In which
454 case he/she should provide a comment about the changes required, alongside the
455 <code>Conflicts
</code> section. Summary of which will be provided in the
456 <a href=
"releasing.html#prerelease">pre-release
</a> announcement.
460 Developers are interested in sending backports are recommended to use either a
461 <code>[BACKPORT #branch]
</code> subject prefix or provides similar information
462 within the commit summary.
465 <h2 id=
"gittips">Git tips
</h2>
468 <li><code>git rebase -i ...
</code> is your friend. Don't be afraid to use it.
469 <li>Apply a fixup to commit FOO.
472 git commit --fixup=FOO
473 git rebase -i --autosquash ...
475 <li>Test for build breakage between patches e.g last
8 commits.
477 git rebase -i
--exec=
"ninja -C build/" HEAD~
8
479 <li>Sets the default mailing address for your repo.
481 git config --local sendemail.to mesa-dev@lists.freedesktop.org
483 <li> Add version to subject line of patch series in this case for the last
8
484 commits before sending.
486 git send-email
--subject-prefix=
"PATCH v4" HEAD~
8
487 git send-email -v4 @~
8 # shorter version, inherited from git format-patch
489 <li> Configure git to use the get_reviewer.pl script interactively. Thus you
490 can avoid adding the world to the CC list.
492 git config sendemail.cccmd
"./scripts/get_reviewer.pl -i"