Re: [igt-dev] [PATCH i-g-t 2/4] lib: Make SLPC helper function per GT

["Dixit, Ashutosh" <ashutosh.dixit@intel.com>]

On Thu, 13 Apr 2023 15:44:12 -0700, Vinay Belgaumkar wrote:
>
> Use default of 0 where GT id is not being used.
>
> Signed-off-by: Vinay Belgaumkar <vinay.belgaumkar@intel.com>
> ---
>  lib/igt_pm.c             | 20 ++++++++++----------
>  lib/igt_pm.h             |  2 +-
>  tests/i915/i915_pm_rps.c |  6 +++---
>  3 files changed, 14 insertions(+), 14 deletions(-)
>
> diff --git a/lib/igt_pm.c b/lib/igt_pm.c
> index 704acf7d..8ca7c181 100644
> --- a/lib/igt_pm.c
> +++ b/lib/igt_pm.c
> @@ -1329,21 +1329,21 @@ void igt_pm_print_pci_card_runtime_status(void)
>	}
>  }
>
> -bool i915_is_slpc_enabled(int fd)
> +bool i915_is_slpc_enabled(int drm_fd, int gt)

OK, we understand that the debugfs dir path is per gt, but I am wondering
if we need to expose this as a function argument? Since, in all instances,
we are always passing gt as 0.

Maybe the caller is only interested in knowing if slpc is enabled. Can SLPC
be enabled for gt 0 and disabled for gt 1? In the case the caller should
really call something like:

	for_each_gt()
		i915_is_slpc_enabled(fd, gt)

and return false if slpc is disabled for any gt.

I think what we should do is write two functions:

1. Rename the function above with the gt argument to something like:

	i915_is_slpc_enabled_gt()

2. Have another function without the gt argument:

	i915_is_slpc_enabled() which will do:

	for_each_gt()
		i915_is_slpc_enabled_gt(fd, gt)

and return false if slpc is disabled for any gt.

And then have the tests call this second function without the gt argument.

I think this will be cleaner than passing 0 as the gt from the tests.

Thanks.
--
Ashutosh


>  {
> -	int debugfs_fd = igt_debugfs_dir(fd);
> -	char buf[4096] = {};
> -	int len;
> +	int debugfs_fd;
> +	char buf[256] = {};
> +
> +	debugfs_fd = igt_debugfs_gt_open(drm_fd, gt, "uc/guc_slpc_info", O_RDONLY);
>
> -	igt_require(debugfs_fd != -1);
> +	/* if guc_slpc_info not present then return false */
> +	if (debugfs_fd < 0)
> +		return false;
> +	read(debugfs_fd, buf, sizeof(buf)-1);
>
> -	len = igt_debugfs_simple_read(debugfs_fd, "gt/uc/guc_slpc_info", buf, sizeof(buf));
>	close(debugfs_fd);
>
> -	if (len < 0)
> -		return false;
> -	else
> -		return strstr(buf, "SLPC state: running");
> +	return strstr(buf, "SLPC state: running");
>  }
>
>  int igt_pm_get_runtime_suspended_time(struct pci_device *pci_dev)
> diff --git a/lib/igt_pm.h b/lib/igt_pm.h
> index d0d6d673..1b054dce 100644
> --- a/lib/igt_pm.h
> +++ b/lib/igt_pm.h
> @@ -84,7 +84,7 @@ void igt_pm_set_d3cold_allowed(struct igt_device_card *card, const char *val);
>  void igt_pm_setup_pci_card_runtime_pm(struct pci_device *pci_dev);
>  void igt_pm_restore_pci_card_runtime_pm(void);
>  void igt_pm_print_pci_card_runtime_status(void);
> -bool i915_is_slpc_enabled(int fd);
> +bool i915_is_slpc_enabled(int fd, int gt);
>  int igt_pm_get_runtime_suspended_time(struct pci_device *pci_dev);
>  int igt_pm_get_runtime_usage(struct pci_device *pci_dev);
>
> diff --git a/tests/i915/i915_pm_rps.c b/tests/i915/i915_pm_rps.c
> index d4ee2d58..85dae449 100644
> --- a/tests/i915/i915_pm_rps.c
> +++ b/tests/i915/i915_pm_rps.c
> @@ -916,21 +916,21 @@ igt_main
>	}
>
>	igt_subtest("basic-api") {
> -		igt_skip_on_f(i915_is_slpc_enabled(drm_fd),
> +		igt_skip_on_f(i915_is_slpc_enabled(drm_fd, 0),
>			      "This subtest is not supported when SLPC is enabled\n");
>		min_max_config(basic_check, false);
>	}
>
>	/* Verify the constraints, check if we can reach idle */
>	igt_subtest("min-max-config-idle") {
> -		igt_skip_on_f(i915_is_slpc_enabled(drm_fd),
> +		igt_skip_on_f(i915_is_slpc_enabled(drm_fd, 0),
>			      "This subtest is not supported when SLPC is enabled\n");
>		min_max_config(idle_check, true);
>	}
>
>	/* Verify the constraints with high load, check if we can reach max */
>	igt_subtest("min-max-config-loaded") {
> -		igt_skip_on_f(i915_is_slpc_enabled(drm_fd),
> +		igt_skip_on_f(i915_is_slpc_enabled(drm_fd, 0),
>			      "This subtest is not supported when SLPC is enabled\n");
>		load_helper_run(HIGH);
>		min_max_config(loaded_check, false);
> --
> 2.38.1
>