Re: Procedure to make the driver into the backports project

[Arend van Spriel <arend@broadcom.com>]

On 06-06-14 01:59, Fariya wrote:
> Hi Arend,
>
> Considering that my driver doesn't compile on kernel versions < the
> latest one, I wanted to submit a patch/patches to handle all kernel
> versions. My question was relating to this - do I need to submit a
> patch [which handles kernel versions from 3.0 to 3.14] or patches for
> each kernel version from 3.0 to 3.14, which when applied on the latest
> driver of mine, would make it compilable for all kernel versions?

The fact that your driver does not compile on non-latest kernels is the 
reason to look at backports project. The alternative is to do it 
manually by creating patches against each target kernel. The backports 
framework tries to avoid that by doing things a tad bit smarter. Key in 
this is that using the driver from backports release package gives an 
additional module called compat.ko. In here all the glue code is present 
that makes your driver work on the older target kernel.

Assuming you have a linux-next tree checked out in ~/linux-next, here 
are a couple of steps you should do:
1. assure you have coccinelle installed.
2. clone the backports repository.
3. add you driver folder to copy-list file.
4. run 'gentree.py ~/linux-next /tmp/backport-rsi-next'.

If this runs successful, you should verify if it works on your machine 
assuming it runs an older kernel:

5. cd /tmp/backport-rsi-next
6. run 'make menuconfig' and select your driver.
7. run 'make'.

Any issues in steps 4 or 7 warrant a patch against backports repo.

Regards,
Arend

> On Fri, Jun 6, 2014 at 3:25 AM, Arend van Spriel <arend@broadcom.com> wrote:
>> On 05-06-14 23:30, Fariya wrote:
>>>
>>> Hello,
>>>
>>> Thanks for answering all my queries so far. I just wanted to clarify
>>> one important thing - The latest backport release is of the kernel
>>> 3.15-rc1-1.
>>> [http://drvbp1.linux-foundation.org/~mcgrof/rel-html/backports/]
>>> So this means I need to submit my patch(es) for this kernel or the
>>> latest kernel available on kernel.org which is 3.15-rc8? Also, can I
>>> send like a single patch which handles all kernels or do I need to
>>> submit patches for each kernel from 3.0 to 3.14?
>>
>>
>> Let's try once more. the release page contains stable releases and
>> development release. The development release is a snapshot taken from
>> linux-next (so including wireless-next) so it has everything you throw at
>> John and gets applied by him. The package can be used to build drivers for a
>> particular target kernel, ie. 3.0 to 3.14. So you don't need to submit any
>> driver patches as the backport packaging script will get simply copy the
>> driver sources from linux-next repository.
>>
>> Regards,
>> Arend
>>
>>
>>> Regards,
>>> Fariya
>>>
>>>
>>> On Thu, Jun 5, 2014 at 3:57 AM, Fariya <fariyaf@gmail.com> wrote:
>>>
>>>> On Thu, May 29, 2014 at 8:09 PM, Arend van Spriel <arend@broadcom.com>
>>>> wrote:
>>>>>
>>>>> On 05/29/14 12:03, Fariya wrote:
>>>>>>
>>>>>>
>>>>>> Hello Arend,
>>>>>>
>>>>>> Thanks for the reply. I do have a few more questions:
>>>>>> a) I kind of went through the existing drivers in the backport release
>>>>>> and found that the framework that you are talking of is more of #ifdef
>>>>>> LINUX_VERSION_CODE>= KERNEL_VERSION() handling for various kernels.
>>>>>> Please correct me if I am wrong.
>>>>>
>>>>>
>>>>>
>>>>> Kind of correct. A backport release is done taking a snapshot of
>>>>> linux-stable and patch it with those ifdef and other tricks. The script
>>>>> taking the snapshot and the patches is what is in the backport repo.
>>>>>
>>>>> Basically, the drivers are copied as is and the kernel functions these
>>>>> driver use are subject to being backported when these functions are not
>>>>> available in the older kernels.
>>>>>
>>>>>
>>>>>> b) How do I ensure that my driver gets into backport repo. Do I need
>>>>>> to send patches [the patch will contain code for various kernels,
>>>>>> handled via the #ifdef LINUX_VERSION_CODE>= .... code?] for my latest
>>>>>> driver onto this e-mail list?
>>>>>
>>>>>
>>>>>
>>>>> The backport takes a snapshot from linux-stable and linux-next so
>>>>> anything
>>>>> you send to John will end up in the backport releases. So you only need
>>>>> to
>>>>> submit something if the backport driver code would not compile, which
>>>>> means
>>>>> some function called in the driver needs backporting.
>>>>>
>>>>>
>>>>>> c) Assuming my driver gets into the backport repo soon, I am wondering
>>>>>> how the future versions of my driver will be backported? [considering
>>>>>> that I would be submitting code compatible to the latest kernel onto
>>>>>> the linux-wireless mailing list] Do I need to send a patch to the
>>>>>> backports mailing list, for any submission that I make to the
>>>>>> linux-wireless mailing list?
>>>>>
>>>>>
>>>>>
>>>>> As mentioned above there is no need unless you want to contribute to the
>>>>> code in the backports repo, ie. the stuff that creates the backport
>>>>> releases.
>>>>>
>>>>> Regards,
>>>>> Arend
>>>>>
>>>>>
>>>>>> On Mon, May 26, 2014 at 7:45 PM, Arend van Spriel<arend@broadcom.com>
>>>>>> wrote:
>>>>>>>
>>>>>>>
>>>>>>> On 05/26/14 15:44, Arend van Spriel wrote:
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> On 05/26/14 11:47, Fariya wrote:
>>>>>>>>>
>>>>>>>>>
>>>>>>>>>
>>>>>>>>> Hi,
>>>>>>>>>
>>>>>>>>> My company's wireless driver is a part of the latest 3.15-rc kernel.
>>>>>>>>> My question is pertaining to the backports project. How does the
>>>>>>>>> procedure at backports work? Will my driver be picked up and
>>>>>>>>> backported by the backports group now that it is part of the kernel
>>>>>>>>> or
>>>>>>>>> the owner of the driver needs to backport the driver [for various
>>>>>>>>> kernels] and provide it on to this mailing list initially?
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> The backport repo does not hold a backported driver, but a framework
>>>>>>>> to
>>>>>>>> create a package of the latest drivers which can be automatically
>>>>>>>> backported to various kernels.
>>>>>>>>
>>>>>>>> When you check out the backports repository on kernel.org there is a
>>>>>>>> copy-list file which lists everything that is copied from the kernel
>>>>>>>> tree to be included in the backport package. First step would be to
>>>>>>>> add
>>>>>>>> you driver to that list. If you are lucky that might be sufficient.
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> However, a quick try over here shows not :-p
>>>>>>>
>>>>>>> /tmp/backporst-rsi/drivers/net/wireless/rsi/rsi_91x_mac80211.c: In
>>>>>>> function
>>>>>>> rsi_mac80211_attach:
>>>>>>> /tmp/backporst-rsi/drivers/net/wireless/rsi/rsi_91x_mac80211.c:988:2:
>>>>>>> error:
>>>>>>> implicit declaration of function ether_addr_copy
>>>>>>> [-Werror=implicit-function-declaration]
>>>>>>> cc1: some warnings being treated as errors
>>>>>>> make[7]: ***
>>>>>>> [/tmp/backporst-rsi/drivers/net/wireless/rsi/rsi_91x_mac80211.o] Error
>>>>>>> 1
>>>>>>>
>>>>>>> Regards,
>>>>>>> Arend
>>>>>>>
>>>>>>>
>>>>>>>> Regards,
>>>>>>>> Arend
>>>>>>>>
>>>>>>>>> Regards,
>>>>>>>>> Fariya
>>>>>>>>> --
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>>>>>>>>> in
>>>>>>>>> the body of a message to majordomo@vger.kernel.org
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>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> --
>>>>>>>> To unsubscribe from this list: send the line "unsubscribe backports"
>>>>>>>> in
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>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>> -Fariya Fatima
>>>
>>>
>>>
>>>
>>
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