ACK/Cmnt: [SRU][K][J, hwe-5.17, oem-5.17, starfive-5.17, allwinner-5.17][PATCH 0/1] Enable CONFIG_GPIO_CDEV_V1

[Stefan Bader]

On 21.07.22 09:40, Emil Renner Berthing wrote:
> On Thu, 21 Jul 2022 at 09:29, Stefan Bader <stefan.bader at canonical.com> wrote:
>> On 20.07.22 15:14, Emil Renner Berthing wrote:
>>> On Wed, 20 Jul 2022 at 15:11, Tim Gardner <tim.gardner at canonical.com> wrote:
>>>> On 7/20/22 04:40, Emil Renner Berthing wrote:
>>>>> [Impact]
>>>>>
>>>>>     * The libgpiod2 library and gpiod tools shipped in Jammy don't work.
>>>>>
>>>>>     * These tools are meant to replace the old sysfs interface and be
>>>>>       a better and more efficient way to manipulate GPIOs from userspace.
>>>>>       Unfortunately the latest release is still using v1 of the character
>>>>>       device kernel API which is not enabled in Ubuntu kernels.
>>>>>
>>>>>     * This is Kent Gibsons reply on the linux-gpio mailing list:
>>>>>
>>>>> On Tue, Jul 12, 2022 at 09:48:45AM +0200, Alexandre Ghiti wrote:
>>>>>> Hi,
>>>>>>
>>>>>> Ubuntu kernels do not enable GPIO_CDEV_V1 as it is deprecated, but the
>>>>>> libgpiod package that we ship is still based on the latest version
>>>>>> 1.6.3 which does not implement the API v2. So I'd like to update
>>>>>> libgpiod, do you have any recommendations about what branch/sha1 I
>>>>>> should use? Do you plan to make a release that implements the API v2?
>>>>>>
>>>>>
>>>>> Firstly, libgpiod is Bart's library so he is the authority, but this
>>>>> is my understanding...
>>>>>
>>>>> TLDR: You should keep GPIO_CDEV_V1 enabled.
>>>>>
>>>>> v1 is deprecated from a development perspective, so all new feature
>>>>> development will occur on v2, and new applications should target v2.
>>>>> Existing apps targetting v1, be that directly or via libgpiod v1.6.3,
>>>>> will require GPIO_CDEV_V1 until they migrate to v2.
>>>>> The mainline kernel will continue to support v1 while userspace
>>>>> transitions.
>>>>>
>>>>> libgpiod v2 is in active development, and should reach its first release
>>>>> shortly.
>>>>> Note that it is NOT a plugin replacement for v1. It has a different API,
>>>>> for similar reasons to why we had to switch in the kernel, so apps will
>>>>> need to be actively migrated.
>>>>>
>>>>> I wouldn't suggest making any effort to package libgpiod v2 until Bart
>>>>> makes an official release.
>>>>>
>>>>> Cheers,
>>>>> Kent.
>>>>>
>>>>> [Test Plan]
>>>>>
>>>>>     * Run gpioinfo on a machine with exposed GPIOs and check that it lists
>>>>>       the GPIOs and doesn't error with
>>>>>
>>>>>       gpioinfo: error creating line iterator: Invalid argument
>>>>>
>>>>> [Where problems could occur]
>>>>>
>>>>>     * There may be code and scripts that hasn't been tested with a working
>>>>>       libgpiod2/gpiod tools and uncover latent bugs.
>>>>>
>>>>> Emil Renner Berthing (1):
>>>>>      UBUNTU: [Config] Enable CONFIG_GPIO_CDEV_V1
>>>>>
>>>>>     debian.master/config/annotations          | 4 +++-
>>>>>     debian.master/config/config.common.ubuntu | 2 +-
>>>>>     2 files changed, 4 insertions(+), 2 deletions(-)
>>>>>
>>>> Acked-by: Tim Gardner <tim.gardner at canonical.com>
>>>>
>>>> The correct form for a Launchpad URL is 'note<LP: #1953613>'
>>>
>>> Ah, I see, thanks. Yeah, the annotations file in kinetic:linux has a
>>> lot of different variations, so I just went with one of the most
>>> common ones.
>>
>> The reasoning here is that with some shell pattern matching magic (not quite
>> sure this is a default or something I installed over time) the form "LP: #123"
>> becomes a link which can be clicked.
> 
> That makes sense, but right now only 1/136 entries in kinetic:linux
> use that form,
> 3/136 if you allow trailing free text.

That is the reason I added the explanation here. I am not sure we are very good 
at explaining WHY something is done a certain way. ;) Feel free to spread the word.

-Stefan

> 
> /Emil
> 
>> -Stefan
>>
>>>
>>> /Emil
>>>> -----------
>>>> Tim Gardner
>>>> Canonical, Inc
>>>
>>

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