Mauro Carvalho Chehab 2006 Jan 30 This file describes the general procedures used by v4l-dvb maintainers. Some of these also applies to patch submitters. We've moved from cvs to a modern SCM system that fits better into kernel development model, called Mercurial (aka hg). At http://selenic.com/mercurial you'll find quick-start info, a tutorial and FAQs. Mercurial is a distributed SCM, which means every developer gets his own full copy of the repository (including the complete revision history), and can work and commit locally without network connection. The resulting changesets can then be exchanged between repositories and finally published to the master repository in linuxtv.org. Mercurial is organized with a master tag, called tip. This tag contains the master repository that will be used by normal users and to generate patches to kernel. The v4l-dvb mercurial repository is meant for development. It means that it might be broken from time to time, although all efforts should be done to avoid this. There are more "stable" snapshots at http://www.linuxtv.org/downloads/snapshot page. This file postulates some simple rules for maintaing hg tree, as stated below: 1) It is strongly recommended that each developer be active at IRC channels (irc://irc.freenode.net) #v4l (for analog) and/or #linuxtv (for digital). It helps to have more discussions at major changes; 2) Minor changes, like simple card additions (for example a new card row at a card struct) can be applied directly by each developer; 3) Medium changes that needs modification on card coding or creating a new card type should be discussed first at the Mailing Lists video4linux-list@redhat.com (analog/common parts) and/or linux-dvb@linuxtv.org to allow other contributors to discuss about the way it will be included. 4) Major changes that implies changing some core structs should be widely discussed on IRC, posted to the list, created a snapshot THEN committed to the tip branch. It is strongly recommended to use a branch or v4l_experimental area for such changes. 5) Every CVS maintainer should follow the "rules of thumb" of kernel development stated at Linux source code, especially: Documentation/SubmittingPatches Documentation/SubmittingDrivers Documentation/CodingStyle 6) All commits should have a consistent message. On v4l-dvb, this is done by using: make commit This will run some scripts that will check changed files, generating a ChangeLog like comment (that will be removed from the commit) and prepare the last Signed-off-by field, as described bellow. 7) Files can be added, removed or renamed at hg repository. This should be done by using: hg add hg remove hg rename hg addremove *Warning* hg addremove will add/removes all files, including object files. Be careful! You can remove wrongly added files with hg remove. 8) If the commit went wrong, hg allows you to undo the last commit, by using the command: hg undo This command will preserve the changes at the files. So, a new hg commit will redo the desired commit. 9) To push the change to the *MASTER* repository you need to run: make push 10) To update from the master repository, it is needed to do: make pull 11) For hg to work properly, these vars should be defined (replacing the names at the left): HGUSER="Maintainer Name" If you use a different login name at the repo, you may use: CHANGE_LOG_LOGIN=my_log_name You may also have it at ~/.hgrc, but, in this case, make commit will not generate From: and Signed-off-by fields automatically. Don't forget to export the vars, like: export CHANGE_LOG_LOGIN HGUSER It is strongly recommended to have these lines at .bashrc or .profile. 12) All commit messages shall have a Developers Certificate of Origin version 1.1 at commit log, as postulated at kernel's source at: Documentation/SubmittingPatches This is done by using Signed-off-by: fields at hg commit message. It is not acceptable to use fake signatures like: Signed-off-by: Fake me The email should be a valid one. The bottom signed-off-by should be the commiter. 13) Commit messages are very relevant, since they will be used when generating the patches for v4l-dvb.git and to mainstream. The format of commit message shall be: patch subject From: Patch Developer patch descriptions Signed-off-by: Patch Developer Signed-off-by: Cvs Maintainer All lines starting with # will be removed by make commit stripts. Subject should be a brief description of the patch. Please notice that, with hg, there's no need (and not desired) to define a Subject: tag. The *first* msg line will be used as subject, just like git. *WARNING* Be careful not to leave the first line blank, otherwise hg will leave subject in blank. From: line shouldn't be suppressed, since it will be used when converting to -git as patch author. You may add other signers, if the patch were tested /co-developed by somebody else and he also wants to sign. The committer signed-off-by should be the last one. 14) If the patch also affects other parts of kernel (like alsa or i2c), it is required that, at upstream submitting, the patch also goes to the maintainers of that subsystem. To do this, CVS maintainer shall add one or more cc: fields to the commit message, after the subject: CC: someotherkerneldeveloper@someplace Please notice that this is manually handled by the -git maintainer, so unnecessary usage should be avoided. 15) Sometimes, mainstream changes do affect v4l-dvb tree, and requires to apply some kernel patches at the tree. This kind of commit should follow the rules above and should also have a line like: kernel-sync Patches with such lines will not be submitted upstream. 16) sometimes it is necessary to introduce some testing code inside a module or remove parts that are not yet finished. Also, compatibility tests may be required to provide backporting. To allow compatibility tests, "compat.h" should be included first. It does include also linux/version.h. To include testing code, #if 0 or #if 1 may be used. If this code is meant to go also to kernel, this struct should be used: #if 0 /* keep */ or #if 1 /* keep */ 17) Nested #ifs are allowed, but the #elif macro shouldn't be used, since the macro preprocessing script used to prepare kernel upstream patches (v4l/scripts/gentree.pl) is not able to handle it. Cheers, Mauro Mauro Carvalho Chehab