[libcamera-devel] [PATCH] meson: detect kernel version

[scerveau]

Hi Kieran,


On 11/6/20 11:53, Kieran Bingham wrote:
> Hi Stéphane
> 
> On 11/06/2020 10:32, scerveau wrote:
>> Hi Kieran,
>>
>> Thank you for your feedback.
>> I updated the message to be shorter and more explicit (I hope).
>>
>> Concerning V4L2 message, yes that's the original issue I was facing :)
>> Not understand what I neeed to do fix this error:
>>
>> V4L2 API v4.15.18 too old, v5.0.0 or later
>>
>> Maybe we should fix this message too :)
> 
Yes but the message is not very obvious as it can be confusing with v4L
library version, dont you think ?

> Aha - so the V4L2VideoDevice already does the check. I see. And that
> will indeed prevent pipelines from being created.
> 
> Below I think I was really just being pedantic about the message
> printed, as it is the kernel version not a 'v4l2 api' version (though
> those are the same thing ultimately).
> 
> 
>>
>> Stéphane.
>>
>> On 11/6/20 11:09, Kieran Bingham wrote:
>>> Hi Stéphane,
>>>
>>> On 11/06/2020 09:43, Stéphane Cerveau wrote:
>>>> Add kernel version detection to warn user
>>>> that only >= 5.0.0 V4L API are supported in
>>>> libcamera.
>>>>
>>>> Signed-off-by: Stéphane Cerveau <scerveau at collabora.com>
>>>> ---
>>>>    meson.build | 8 ++++++++
>>>>    1 file changed, 8 insertions(+)
>>>>
>>>> diff --git a/meson.build b/meson.build
>>>> index e898782..a72fef6 100644
>>>> --- a/meson.build
>>>> +++ b/meson.build
>>>> @@ -105,6 +105,14 @@ if get_option('test')
>>>>        subdir('test')
>>>>    endif
>>>>    +if not meson.is_cross_build()
>>>> +  kernel_version_req = '>= 5.0.0'
>>>> +  kernel_version = run_command('uname', '-r').stdout()
>>>
>>>> meson.build:112: WARNING: V4L2 API version 5.4.0-33-generic
>>>>    is too old, >= 5.8.0 is required, consider to upgrade your kernel
>>>> version to use libcamera
>>>
>>> This needs a .strip() at the end to remove the new lines:
>>>
>>>> +  if not kernel_version.version_compare(kernel_version_req)
>>>> +    warning('V4L2 API version @0@ is too old, @1@ is required,
>>>> consider to upgrade your kernel version to use
>>> libcamera'.format(kernel_version, kernel_version_req))
>>>
>>> That line is really long, can it be reduced? At the very least, the
>>> .format() can move to a new line I believe.
>>>
>>>
>>> Grammatically I think this should be :
>>>    "consider upgrading your"
>>> rather than
>>>    "consider to upgrade"
>>>
>>> but that's longer ;-(
>>>
>>>
>>> "WARNING: V4L2 API version 5.4.0-33-generic"
>>>
>>> That's not really the V4L2 API version (I mean I guess it is) but it's
>>> the Linux-kernel version...
>>>
>>> So I wouldn't reference the V4L2 API there ...
>>>
>>>
>>>> +  endif
>>>> +endif
>>>> +
>>>>    # Create a symlink from the build root to the source root. This is
>>>> used when
>>>>    # running libcamera from the build directory to locate resources in
>>>> the source
>>>>    # directory (such as IPA configuration files).
>>>>
>>>
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>