[PATCH i-g-t v4 1/2] lib/igt_pm: Introduce helper to check for PM capability

[Kamil Konieczny]

Hi Jakub,
On 2025-03-18 at 15:01:07 +0000, Jakub Kolakowski wrote:
> Introduce igt_has_pci_pm_capability(), a helper function to check
> whether a PCI device supports the PCI Power Management (PM) capability.
> With this helper one can make sure the capability is present on device
> under test before proceeding with any actions related to PM.
> 
> Cc: Adam Miszczak <adam.miszczak at linux.intel.com>
> Cc: Lukasz Laguna <lukasz.laguna at intel.com>
> Cc: Marcin Bernatowicz <marcin.bernatowicz at linux.intel.com>
> Signed-off-by: Jakub Kolakowski <jakub1.kolakowski at intel.com>

Reviewed-by: Kamil Konieczny <kamil.konieczny at linux.intel.com>

> ---
>  lib/igt_pm.c | 19 ++++++++++++++++++-
>  lib/igt_pm.h |  1 +
>  2 files changed, 19 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/igt_pm.c b/lib/igt_pm.c
> index 1a5d9c42b..7f9cbd69a 100644
> --- a/lib/igt_pm.c
> +++ b/lib/igt_pm.c
> @@ -40,10 +40,11 @@
>  #include <dirent.h>
>  
>  #include "drmtest.h"
> +#include "igt_aux.h"
>  #include "igt_device_scan.h"
>  #include "igt_kms.h"
> +#include "igt_pci.h"
>  #include "igt_pm.h"
> -#include "igt_aux.h"
>  #include "igt_sysfs.h"
>  
>  /**
> @@ -81,6 +82,7 @@ enum {
>  #define MAX_POLICY_STRLEN	strlen(MAX_PERFORMANCE_STR)
>  /* Root Port bus can have max 32 dev and each dev can have max 8 func */
>  #define MAX_PCI_DEVICES		256
> +#define PCI_PM_CAP_ID 0x01
>  int8_t *__sata_pm_policies;
>  int __scsi_host_cnt;
>  
> @@ -1470,3 +1472,18 @@ void igt_pm_ignore_slpc_efficient_freq(int i915, int gtfd, bool val)
>  	igt_require(igt_sysfs_has_attr(gtfd, "slpc_ignore_eff_freq"));
>  	igt_sysfs_set_u32(gtfd, "slpc_ignore_eff_freq", val);
>  }
> +
> +/**
> + * igt_has_pci_pm_capability:
> + * @pci_dev: PCI device struct
> + *
> + * Returns: true if the device has PCI Power Management capability, false otherwise.
> + */
> +bool igt_has_pci_pm_capability(struct pci_device *pci_dev)
> +{
> +	int offset;
> +
> +	offset = find_pci_cap_offset(pci_dev, PCI_PM_CAP_ID);
> +
> +	return (offset > 0);
> +}
> diff --git a/lib/igt_pm.h b/lib/igt_pm.h
> index 6b428f53e..c73972f2a 100644
> --- a/lib/igt_pm.h
> +++ b/lib/igt_pm.h
> @@ -97,5 +97,6 @@ uint64_t igt_pm_get_runtime_suspended_time(struct pci_device *pci_dev);
>  uint64_t igt_pm_get_runtime_active_time(struct pci_device *pci_dev);
>  int igt_pm_get_runtime_usage(struct pci_device *pci_dev);
>  void igt_pm_ignore_slpc_efficient_freq(int i915, int gtfd, bool val);
> +bool igt_has_pci_pm_capability(struct pci_device *pci_dev);
>  
>  #endif /* IGT_PM_H */
> -- 
> 2.34.1
>