As already discussed during the -git announcement, one important part is how
we'll handle -git pushes.
So, I'm sending a procedure explaining how should be the new submission process
for
sending patches via GIT PULL requests.
Feel free to comment and send suggestions to improve it. I intend to add its
content
to README.patches or to add it as README.git next week, after getting some
review.
Cheers,
Mauro
---
Mauro Carvalho Chehab <mchehab at infradead dot org> Updated on 2010 January
23
1. KERNEL DEVELOPMENT PROCEDURES FOR UPSTREAM
=============================================
Before starting with the RFC, it is important that people understand how
upstream
development works.
Kernel development has 2 phases:
1) a merge window typically with 2 weeks (although Linus is gave some
indications that he may reduce it on 2.6.34), starting with the release
of a new kernel version;
2) the -rc period, where the Kernel is tested and receive fixes.
The length of the -rc period depends on the number and relevance of the fixes.
Considering
the recent history, it ranges from -rc6 to -rc8, where each -rc takes one week.
Those are the latest -rc kernels since 2.6.12:
2.6.12-rc6
2.6.13-rc7
2.6.14-rc5
2.6.15-rc7
2.6.16-rc6
2.6.17-rc6
2.6.18-rc7
2.6.19-rc6
2.6.20-rc7
2.6.21-rc7
2.6.22-rc7
2.6.23-rc9
2.6.24-rc8
2.6.25-rc9
2.6.26-rc9
2.6.27-rc9
2.6.28-rc9
2.6.29-rc8
2.6.30-rc8
2.6.31-rc9
2.6.32-rc8
In general, the announcement of a new -rc kernel gives some hints when that -rc
kernel
may be the last one.
The required procedure, on subsystem trees is that:
a) During -rc period (e.g. latest main kernel available is 2.6.x, the latest
-rc kernel
is 2.6.[x+1]-rc<y>):
- fix patches for the -rc kernel (2.6.[x+1]) should be sent upstream,
being a good idea to send them for some time at linux-next tree, allowing other
people to test it, and check for potential conflicts with the other arch's;
- patches for 2.6.[x+2] should be sent to linux-next.
b) the release of 2.6.[x+1] kernel:
- closes the -rc period and starts the merge window.
c) During the merge window:
- the patch that were added on linux-next during the -rc period
for 2.6.[x+2] should be sent upstream;
- new non-fix patches should be hold until the next -rc period starts,
so, they'll be added on 2.6.[x+3];
- fix patches for 2.6.[x+2] should go to linux-next, wait for a few days
and then send upstream.
d) the release of 2.6.[x+2]-rc1 kernel:
- the merge window has closed. No new features are allowed.
- the patches with new features that arrived during the merge window
will
be moved to linux-next
So, in other words, as currently x=32, and we are at the -rc period, being that
the latest stable kernel is 2.6.32 and the latest -rc kernel 2.6.33-rc5, we are
receiving
patches for new features that will be available on kernel 2.6.34. After the
release
of 2.6.33, new features we receive will be added on 2.6.35.
So, we're always developing features that will be there on the next 2 kernels.
In the specific case of new drivers that don't touch on existing features, it
could
be possible to send it during the -rc period, but it is safer to assume that
those
drivers should follow the above procedure, as a later submission may be nacked.
Sometimes, a fix patch corrects a problem that happens also on stable kernels
(e. g.
on kernel 2.6.x or even 2.6.y, where y < x). In this case, the patch should be
sent to
sta...@kernel.org, in order to be added on stable kernels.
2. KERNEL DEVELOPMENT PROCEDURES FOR V4L/DVB
============================================
That's the RFC on how we should work with -git.
1) fixes and linux-next patches
One of the big problems of our model is that we're using just one tree/branch
for everything,
with mercurial. This makes hard to send some fix patches for 2.6.[x+1], as they
may have conflicts
with the patches for 2.6.[x+2]. So, when the conflict is simple to solve, the
patch is sent as
fixes. Otherwise, it generally is hold to the next cycle. The fix patches
should be tagged by the
developer with "Priority: high" on mercurial.
Unfortunately, sometimes people mark the driver with the wrong tag. For
example, I merged yesterday
a patch marked with "high" that doesn't apply at the fixes tree. This patch fix
a regression introduced
by a driver that weren't merged yet, so, the patch were added as normal patch.
How to solve those issues?
Well, basically, we should work with more than one tree (or branch), on
upstream submission:
a tree/branch with the fix patches;
a tree/branch with the new feature patches.
So, the idea is that we'll use those two -git trees:
http://linuxtv.org/git//v4l-dvb.git - Patches for linux-next
http://linuxtv.org/git//fixes.git - Patches for upstream
While we'll keep accepting patches via -hg, due to the merge conflicts its
mentioned, the better is that,
even those developers that prefer to develop patches use the old way, to send
us the fixes via -git.
This way, if is there a conflict, he is the one that can better solve it. Also,
it avoids the risk of
a patch being wrongly tagged.
Also, after having a patch added on one of the above trees, we can't simply
remove it, as others will
be cloning that tree. So, the only option would be to send a revert patch,
causing the patch history
to be dirty and could be resulting on some troubles when submitting upstream.
I've seen some nacks on
receiving patches upstream from dirty git trees. So, we should really avoid
this.
2) how to submit a -git pull request
As the same git tree may have more than one branch, and we'll have 2 -git trees
for upstream, it is required
that people specify what should be done. Internally, my workflow is based on
different mail queues for
each type of requesting I receive. I have some scripts here to automate the
proccess, so it is important
that everyone sends me -git pull requests at the same way.
So, I'm basically proposing that a -git pull request to be send with the
following email tags:
From: <your real email>
Subject: [GIT FIX FOR 2.6.33] Fixes for driver cx88
To: linux-media@vger.kernel.org
The from line may later be used by the git mailbomb script to send you a copy
when the patch were committed,
so it should be your real email.
The indication between [] on the subject will be handled by my mailer to put
the request at the right
queue. So, if tagged wrong, it may not be committed.
Don't send a copy of the pull to my addresses. I'll be filtering based on the
subject and on the mailing list.
If you send a c/c to me, it will be simply discarded.
NEVER send a copy of any pull request to a subscribers-only mailing list.
Everyone is free to answer to the
email, reviewing your patches. Don't penalty people that wants to contribute
with you with SPAM bouncing emails,
produced by subscribers only lists.
When a patch touches on other subsystem codes, please copy the other subsystem
maintainers. This is important
for patches that touches on arch files, and also for -alsa non-trivial patches.
The first line in the body should specify the tree and the branch. Something
like:
Please pull from: git://linuxtv.org//mcctest/linux-2.6.git master
Always send me the -git URL, followed by the branch name, both on the same
line. The scripts will
discard any comments that may appear before the tree/branch, but I'll read the
entire email.
At the email, please always send a summary of what's being send. Such summary
is produced by
this commands:
git diff -M --stat --summary $ORIGIN `git branch |grep ^\*|cut -b3-`
echo
git log --pretty=short $ORIGIN..|git shortlog
where $ORIGIN is the commit hash of the tree before your patches.
For example, for the patches merged directly from -hg on my -git trees on Jan,
22 2010,
the above commands will produce:
drivers/media/common/tuners/tuner-xc2028.c | 11 +-
drivers/media/dvb/dm1105/Kconfig | 1 +
drivers/media/dvb/dm1105/dm1105.c | 501 ++++++++++++++-------------
drivers/media/video/cx18/Kconfig | 11 +
drivers/media/video/cx18/Makefile | 2 +
drivers/media/video/cx18/cx18-alsa-main.c | 293 ++++++++++++++++
drivers/media/video/cx18/cx18-alsa-mixer.c | 191 ++++++++++
drivers/media/video/cx18/cx18-alsa-mixer.h | 23 ++
drivers/media/video/cx18/cx18-alsa-pcm.c | 353 +++++++++++++++++++
drivers/media/video/cx18/cx18-alsa-pcm.h | 27 ++
drivers/media/video/cx18/cx18-alsa.h | 59 ++++
drivers/media/video/cx18/cx18-driver.c | 40 ++-
drivers/media/video/cx18/cx18-driver.h | 10 +
drivers/media/video/cx18/cx18-fileops.c | 6 +-
drivers/media/video/cx18/cx18-fileops.h | 3 +
drivers/media/video/cx18/cx18-mailbox.c | 46 +++-
drivers/media/video/cx18/cx18-streams.c | 2 +
drivers/media/video/cx25840/cx25840-core.c | 48 ++-
drivers/media/video/ivtv/ivtv-irq.c | 5 +-
drivers/media/video/ivtv/ivtv-streams.c | 6 +-
drivers/media/video/ivtv/ivtv-udma.c | 1 +
drivers/media/video/pvrusb2/pvrusb2-hdw.c | 1 +
drivers/media/video/saa7134/saa7134-cards.c | 4 +-
include/media/v4l2-subdev.h | 1 +
24 files changed, 1380 insertions(+), 265 deletions(-)
create mode 100644 drivers/media/video/cx18/cx18-alsa-main.c
create mode 100644 drivers/media/video/cx18/cx18-alsa-mixer.c
create mode 100644 drivers/media/video/cx18/cx18-alsa-mixer.h
create mode 100644 drivers/media/video/cx18/cx18-alsa-pcm.c
create mode 100644 drivers/media/video/cx18/cx18-alsa-pcm.h
create mode 100644 drivers/media/video/cx18/cx18-alsa.h
Andy Walls (4):
V4L/DVB: cx25840, v4l2-subdev, ivtv, pvrusb2: Fix ivtv/cx25840 tinny audio
V4L/DVB: ivtv: Adjust msleep() delays used to prevent tinny audio and PCI
bus hang
V4L/DVB: cx18-alsa: Initial non-working cx18-alsa files
V4L/DVB: cx18-alsa: Add non-working cx18-alsa-pcm.[ch] files to avoid
data loss
Devin Heitmueller (20):
V4L/DVB: xc3028: fix regression in firmware loading time
V4L/DVB: cx18: rename cx18-alsa.c
V4L/DVB: cx18: make it so cx18-alsa-main.c compiles
V4L/DVB: cx18: export a couple of symbols so they can be shared with
cx18-alsa
V4L/DVB: cx18: overhaul ALSA PCM device handling so it works
V4L/DVB: cx18: add cx18-alsa module to Makefile
V4L/DVB: cx18: export more symbols required by cx18-alsa
V4L/DVB: cx18-alsa: remove unneeded debug line
V4L/DVB: cx18: rework cx18-alsa module loading to support automatic
loading
V4L/DVB: cx18: cleanup cx18-alsa debug logging
V4L/DVB: cx18-alsa: name alsa device after the actual card
V4L/DVB: cx18-alsa: remove a couple of warnings
V4L/DVB: cx18-alsa: fix memory leak in error condition
V4L/DVB: cx18-alsa: fix codingstyle issue
V4L/DVB: cx18-alsa: codingstyle fixes
V4L/DVB: cx18: codingstyle fixes
V4L/DVB: cx18-alsa: codingstyle cleanup
V4L/DVB: cx18-alsa: codingstyle cleanup
V4L/DVB: cx18: address possible passing of NULL to snd_card_free
V4L/DVB: cx18-alsa: Fix the rates definition and move some buffer freeing
code.
Ian Armstrong (1):
V4L/DVB: ivtv: Fix race condition for queued udma transfers
Igor M. Liplianin (4):
V4L/DVB: Add Support for DVBWorld DVB-S2 PCI 2004D card
V4L/DVB: dm1105: connect splitted else-if statements
V4L/DVB: dm1105: use dm1105_dev & dev instead of dm1105dvb
V4L/DVB: dm1105: use macro for read/write registers
JD Louw (1):
V4L/DVB: Compro S350 GPIO change
This helps to identify what's expected to be found at the -git tree and to
double
check if the merge happened fine.
3) Tags that a patch receive after its submission
This is probably the most complex issue to solve. So, I'd like to see some
suggestions here.
Signed-off-by/Acked-by/Tested-by/Nacked-by tags may be received after a patch
or a -git
submission. This can happen even while the patch is being tested at linux-next,
from
people reporting problems on the existing patches, or reporting that a patch
worked fine.
Also, the driver maintainer and the subsystem maintainer that is committing
those patches
should sign each one, to indicate that he reviewed and has accepted the patch.
Currently, if a new tag is added to a committed patch, its hash will change. I
saw some
discussions about allowing adding new tags on -git without changing the hash,
but I think
this weren't implemented (yet?).
The same problem occurs with -hg, but, as -hg doesn't support multiple branches
(well, it
has a "branch" command, but the concept of branch there is different), it was
opted that
the -hg trees won't have all the needed SOBs. Instead, those would be added
only at the
submission tree.
With -git, a better procedure can be used:
The developer may have two separate branches on his tree. For example, let's
assume that the
developer has the following branches on his tree:
- media-master (associated with "linuxtv" remote)
- fixes
- devel
His development happens on devel branch. When the patches are ready to
submission will be
copied into a new for_submission branch:
git branch for_submission devel
And a pull request from the branch "for_submission" will be sent.
Eventually, he'll write new patches on his devel branch.
After merged, the developer updates the linuxtv remote and drops the
for_submission branch.
This way, "media-master" will contain his patches that got a new hash, due to
the maintainer's
SOB. However, he has some new patches on his devel, that applies over the old
hashes.
Fortunately, git has a special command to automatically remove the old objects:
git rebase.
All the developer needs to do is:
git remote update # to update his remotes, including "linuxtv"
git checkout devel # move to devel branch
git pull . media-master # to make a recursive merge from v4l/dvb
upstream
git rebase media-master # to remove the legacy hashes
After this, his development branch will contain only upstream patches + the new
ones he added
after sending the patches for upstream submission.
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