On 01/09/19 22:15, Antonio Ospite wrote:
> On Mon, 7 Jan 2019 11:18:58 +0100
> Hans Verkuil <[email protected]> wrote:
>
>> On 01/03/2019 07:01 PM, Antonio Ospite wrote:
>>> Add a new option --list-ctrls-values to list the values of controls in
>>> a format which can be passed again to --set-ctrl.
>>>
>>> This can be useful to save and restore device settings:
>>>
>>> $ v4l2-ctl --list-ctrls-values >settings.txt 2>/dev/null
>>> $ v4l2-ctl --set-ctrl "$(cat settings.txt)"
>>>
>>> The new option has been tested with the vivid driver and it works well
>>> enough to be useful with a real driver as well.
>>>
>>> String controls are not supported for now, as they may not be parsed
>>> correctly by --set-ctrl if they contain a comma or a single quote.
>>>
>>> Signed-off-by: Antonio Ospite <[email protected]>
>>> ---
>>> utils/v4l2-ctl/v4l2-ctl-common.cpp | 72 ++++++++++++++++++++++++++----
>>> utils/v4l2-ctl/v4l2-ctl.1.in | 4 ++
>>> utils/v4l2-ctl/v4l2-ctl.cpp | 1 +
>>> utils/v4l2-ctl/v4l2-ctl.h | 1 +
>>> 4 files changed, 69 insertions(+), 9 deletions(-)
>>>
>>> diff --git a/utils/v4l2-ctl/v4l2-ctl-common.cpp
>>> b/utils/v4l2-ctl/v4l2-ctl-common.cpp
>>> index 7777b45c..b4124608 100644
>>> --- a/utils/v4l2-ctl/v4l2-ctl-common.cpp
>>> +++ b/utils/v4l2-ctl/v4l2-ctl-common.cpp
> [...]
>>> @@ -1102,13 +1146,23 @@ void common_get(cv4l_fd &_fd)
>>>
>>> void common_list(cv4l_fd &fd)
>>> {
>>> - if (options[OptListCtrls] || options[OptListCtrlsMenus]) {
>>> - struct print_format classic_format = {
>>> - .print_class_name = print_class_name,
>>> - .print_qctrl = print_qctrl,
>>> - .show_menus = options[OptListCtrlsMenus],
>>> - };
>>> -
>>> - list_controls(fd.g_fd(), &classic_format);
>>> + if (options[OptListCtrls] || options[OptListCtrlsMenus] ||
>>> options[OptListCtrlsValues]) {
>>> + if (options[OptListCtrlsValues]) {
>>> + struct print_format machine_format = {
>>> + .print_class_name = NULL,
>>> + .print_qctrl = print_qctrl_values,
>>> + .show_menus = 0,
>>> + };
>>> +
>>> + list_controls(fd.g_fd(), &machine_format);
>>> + } else {
>>> + struct print_format classic_format = {
>>> + .print_class_name = print_class_name,
>>> + .print_qctrl = print_qctrl,
>>> + .show_menus = options[OptListCtrlsMenus],
>>> + };
>>> +
>>> + list_controls(fd.g_fd(), &classic_format);
>>> + }
>>
>> I don't like this struct print_format.
>>
>
> Hi Hans,
>
> the idea was based on two considerations:
> 1. decide the format once and for all, avoiding to check each time a
> control is printed.
> 2. have at least some partial infrastructure in case some
> other export formats were to be added.
>
> But yeah, as 2. seems quite unlikely I can go with a more essential
> approach for now, no problem.
>
>> I would prefer something like this:
>>
>> Rename print_qctrl to print_qctrl_readable() and create a new print_qctrl:
>>
>> static void print_qctrl(int fd, struct v4l2_query_ext_ctrl *queryctrl,
>> struct v4l2_ext_control *ctrl, int show_menus)
>> {
>> if (options[OptListCtrlsValues])
>> print_qctrl_values(fd, queryctrl, ctrl, show_menus);
>> else
>> print_qctrl_readable(fd, queryctrl, ctrl, show_menus);
>> }
>>
>
> Since "readable" here means "human readable", while "values" is meant
> for a "machine readable" output, I'd "avoid" the word "readable" at
> all and go with "details" or "description":
>
> if (options[OptListCtrlsValues])
> print_qctrl_values(fd, queryctrl, ctrl, show_menus);
> else
> print_qctrl_details(fd, queryctrl, ctrl, show_menus);
Hmm. Perhaps we should just be explicit:
print_qctrl_machine_readable
print_qctrl_human_readable
I think that's best.
>
>> And in print_control you can just skip printing the class name if
>> options[OptListCtrlsValues] is set.
>>
>
> OK.
>
>> I would like to see string controls being supported. I would recommend
>> to just write the string as a hexdump. It avoids having to escape characters.
>>
>> The same can be done for compound/array controls. In fact, you could write
>> all controls that way. It would simplify things a lot.
>>
>
> But then --set-ctrl would need to be extended to parse the hexdump,
> wouldn't it? Do you already have a syntax in mind?
I would add a new --set-ctrl-value option that takes a hexdump.
Basically the inverse of --list-ctrls-values.
Regards,
Hans
>
> TBH, I kept things simple hoping to re-use --set-ctrl without too much
> work.
>
>> Also, when options[OptListCtrlsValues] is set you should skip all WRITE_ONLY
>> controls, all BUTTON controls, and all volatile controls. They are not
>> relevant if you are just interested in controls that can be set.
>>
>
> That I will do in any case, thank you.
>
>> Regards,
>>
>> Hans
>
> Thank you,
> Antonio
>
