[PATCH i-g-t] intel_reg: Stop warning if register spec is not there

[Lucas De Marchi]

On Thu, Apr 11, 2024 at 11:53:03AM +0300, Jani Nikula wrote:
>On Wed, 10 Apr 2024, Lucas De Marchi <lucas.demarchi at intel.com> wrote:
>> Stop suffering when using igt from the git checkout, which is the case
>> for all/most developers.
>>
>> 	$ sudo ./build/tools/intel_reg write 0x2358 0xdeadbeef
>> 	Warning: stat '/usr/local/share/igt-gpu-tools/registers' failed: No such file or directory. Using builtin register spec.
>>
>> Pretty annoying when you have a bunch of commands to run and don't want
>> to simply ignore stderr.  Keep the other warnings as if the file is
>> there and can't be read for some reason, it's good to give a warning.
>> However if the file simply isn't there, let it pass.
>
>The TL;DR is,
>
>Acked-by: Jani Nikula <jani.nikula at intel.com>
>
>---
>
>We have the "register specs" in plain text files so that anyone could
>update them at runtime without building the source. And conceivably they
>could be generated from a more authoritative source. It would be nice if
>we could incorporate the info to the binary at build time as the builtin
>register specs (so no data dir lookups at all), but also be able to
>override them e.g. using a command-line parameter if the user wishes.
>
>I don't think that would even be so hard. But it would arguably be a bit
>wasted effort as long as the register files under tools/registers/
>aren't updated for newer platforms. (The current builtin register specs
>are completely out of date.)

I don't really get why one would want the tools/registers actually. When
I'm using intel_reg I'm already working on a very low level interface
with the hardware and can simply pass/read the raw offsets.

I think a reg spec like that is nice when we are e.g. tracing, so we
don't have to lookup all the registers that are showing up. I think
Gustavo had something wip related to that. However for intel_reg I don't
have a use case.

Lucas De Marchi

>
>The tool could use some love again. It's been almost 10 years since
>commit dfda0b6aecce ("intel_reg: introduce one intel_reg tool to rule
>them all").
>
>BR,
>Jani.
>
>>
>> Signed-off-by: Lucas De Marchi <lucas.demarchi at intel.com>
>> ---
>>  tools/intel_reg.c | 6 +-----
>>  1 file changed, 1 insertion(+), 5 deletions(-)
>>
>> diff --git a/tools/intel_reg.c b/tools/intel_reg.c
>> index 6c37e14d1..ec311a05a 100644
>> --- a/tools/intel_reg.c
>> +++ b/tools/intel_reg.c
>> @@ -1114,12 +1114,8 @@ static int read_reg_spec(struct config *config)
>>  		path = IGT_DATADIR"/registers";
>>
>>  	r = stat(path, &st);
>> -	if (r) {
>> -		fprintf(stderr, "Warning: stat '%s' failed: %s. "
>> -			"Using builtin register spec.\n",
>> -			path, strerror(errno));
>> +	if (r)
>>  		goto builtin;
>> -	}
>>
>>  	if (S_ISDIR(st.st_mode)) {
>>  		r = get_reg_spec_file(buf, sizeof(buf), path, config->devid);
>
>-- 
>Jani Nikula, Intel