[igt-dev] [PATCH i-g-t 5/7] igt/params: add generic saving module parameter set

[Juha-Pekka Heikkila]

On 5.5.2020 10.16, Petri Latvala wrote:
> On Tue, Apr 28, 2020 at 11:22:53PM +0300, Juha-Pekka Heikkila wrote:
>> From: Jani Nikula <jani.nikula at intel.com>
>>
>> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>> Signed-off-by: Juha-Pekka Heikkila <juhapekka.heikkila at gmail.com>
>> ---
>>   lib/igt_params.c | 57 ++++++++++++++++++++++++++++++++++++++++--------
>>   lib/igt_params.h |  3 +++
>>   2 files changed, 51 insertions(+), 9 deletions(-)
>>
>> diff --git a/lib/igt_params.c b/lib/igt_params.c
>> index fe4b1df3..d9cf986c 100644
>> --- a/lib/igt_params.c
>> +++ b/lib/igt_params.c
>> @@ -153,6 +153,29 @@ int igt_params_open(int device)
>>   	return __igt_params_open(device, NULL);
>>   }
>>   
>> +__attribute__((format(printf, 3, 0)))
>> +static bool __igt_params_set(int device, const char *parameter,
>> +			     const char *fmt, va_list ap, bool save)
>> +{
>> +	char *path = NULL;
>> +	int dir;
>> +	int ret;
>> +
>> +	dir = __igt_params_open(device, save ? &path : NULL);
>> +	if (dir < 0)
>> +		return false;
>> +
>> +	if (save)
>> +		igt_params_save(dir, path, parameter);
>> +
>> +	ret = igt_sysfs_vprintf(dir, parameter, fmt, ap);
>> +
>> +	close(dir);
>> +	free(path);
>> +
>> +	return ret > 0;
>> +}
>> +
>>   /**
>>    * igt_params_set:
>>    * @device: fd of the device
>> @@ -164,20 +187,36 @@ int igt_params_open(int device)
>>   bool igt_params_set(int device, const char *parameter, const char *fmt, ...)
>>   {
>>   	va_list ap;
>> -	int dir;
>> -	int ret;
>> -
>> -	dir = igt_params_open(device);
>> -	if (dir < 0)
>> -		return false;
>> +	bool ret;
>>   
>>   	va_start(ap, fmt);
>> -	ret = igt_sysfs_vprintf(dir, parameter, fmt, ap);
>> +	ret = __igt_params_set(device, parameter, fmt, ap, false);
>>   	va_end(ap);
>>   
>> -	close(dir);
>> +	return ret;
>> +}
>>   
>> -	return ret > 0;
>> +/**
>> + * igt_params_set_save:
>> + * @device: fd of the device or -1 to default to first matching starting from
>> + *	    zero. See __igt_params_open()
> 
> 
> This documentation is still only understandable if you already know what it does.
> 
> "-- to default to the first /dev/dri/cardX device, starting from zero" ?
> 
> "See <a function without documentation>" in generated documentation is
> less than useful as well... Maybe just drop that sentence altogether
> from docs, point to the function in a normal comment? Or link to
> igt_debugfs_path() that will do the actual -1 handling...
> 
> With better docs,
> Reviewed-by: Petri Latvala <petri.latvala at intel.com>

These were generally in line with how sysfs was documented but I agree 
it's more fun to read code where there are more hints on what's going 
on. I'll checkout those comment blocks what's all the stuff that could 
be said there.

> 
> 
> 
>> + * @parameter: the name of the parameter to set
>> + * @fmt: printf-esque format string
>> + *
>> + * Save the original value to be restored.
>> + *
>> + * Returns true on success
>> + */
>> +bool igt_params_set_save(int device, const char *parameter, const char *fmt, ...)
>> +{
>> +	va_list ap;
>> +	bool ret;
>> +
>> +	va_start(ap, fmt);
>> +	ret = __igt_params_set(device, parameter, fmt, ap, true);
>> +	va_end(ap);
>> +
>> +	return ret;
>>   }
>>   
>>   /**
>> diff --git a/lib/igt_params.h b/lib/igt_params.h
>> index 52eed77f..1b750d23 100644
>> --- a/lib/igt_params.h
>> +++ b/lib/igt_params.h
>> @@ -31,6 +31,9 @@ int igt_params_open(int device);
>>   __attribute__((format(printf, 3, 4)))
>>   bool igt_params_set(int device, const char *parameter, const char *fmt, ...);
>>   
>> +__attribute__((format(printf, 3, 4)))
>> +bool igt_params_set_save(int device, const char *parameter, const char *fmt, ...);
>> +
>>   void igt_set_module_param(const char *name, const char *val);
>>   void igt_set_module_param_int(const char *name, int val);
>>   
>> -- 
>> 2.26.0
>>
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