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

[Tim Gardner]

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>'

-- 
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Tim Gardner
Canonical, Inc