Re: [PATCH i-g-t v4 1/1] tests/kms_concurrent: Add SYSVIPC support check

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Oct 08, 2025 at 11:18:12AM +0530, S Sebinraj wrote:
> Check for System V IPC support in kms_concurrent test to handle
> targets that don't have SYSVIPC enabled in their kernel. Without this
> check, the test would fail with assertion errors when trying to use
> message queues.
> 
> The implementation checks if the target supports IPC,
> if not found it skips the test.
> 
> Signed-off-by: S Sebinraj <s.sebinraj@intel.com>
> ---
>  lib/intel_allocator.c  | 25 ++++++++++++++++++++++++-
>  lib/intel_allocator.h  | 10 +++++++++-
>  tests/kms_concurrent.c |  4 +++-
>  3 files changed, 36 insertions(+), 3 deletions(-)
> 
> diff --git a/lib/intel_allocator.c b/lib/intel_allocator.c
> index d22c70f1f..fef286e35 100644
> --- a/lib/intel_allocator.c
> +++ b/lib/intel_allocator.c
> @@ -839,14 +839,21 @@ void __intel_allocator_multiprocess_start(void)
>   *
>   * Note. This destroys all previously created allocators and theirs content.
>   */
> -void intel_allocator_multiprocess_start(void)
> +bool intel_allocator_multiprocess_start(void)
>  {
>  	alloc_info("allocator multiprocess start\n");
>  
> +	if (!device_supports_sysvipc()) {
> +		igt_warn("Device does not support SYSVIPC, multiprocess not supported\n");
> +		return false;
> +	}
> +
>  	igt_assert_f(child_pid == -1,
>  		     "Allocator thread can be spawned only in main IGT process\n");
>  	__intel_allocator_multiprocess_prepare();
>  	__intel_allocator_multiprocess_start();
> +
> +	return true;
>  }
>  
>  /**
> @@ -879,6 +886,22 @@ void intel_allocator_multiprocess_stop(void)
>  	}
>  }
>  
> +/**
> + * Checks if the current device supports SYSVIPC by verifying the existence and accessibility
> + * of the /proc/sysvipc directory.
> + * Returns: true if accessible for read and write, false otherwise.
> + */
> +bool device_supports_sysvipc(void)

"device" makes me think of the drm device/gpu. "system" or something would
seem better. 

> +{
> +	char path[128] = {'\0'};
> +
> +	snprintf(path, sizeof(path), "/proc/sysvipc");

What? Just pass the string directly to access.

> +	if (access(path, R_OK | W_OK) == 0)
> +		return true;
> +
> +	return false;
> +}
> +
>  static void track_ahnd(int fd, uint64_t ahnd, uint32_t vm)
>  {
>  	struct ahnd_info *ainfo;
> diff --git a/lib/intel_allocator.h b/lib/intel_allocator.h
> index 4b6292f06..24ce6dbfa 100644
> --- a/lib/intel_allocator.h
> +++ b/lib/intel_allocator.h
> @@ -166,9 +166,17 @@ struct intel_allocator {
>  void intel_allocator_init(void);
>  void __intel_allocator_multiprocess_prepare(void);
>  void __intel_allocator_multiprocess_start(void);
> -void intel_allocator_multiprocess_start(void);
> +bool intel_allocator_multiprocess_start(void);
>  void intel_allocator_multiprocess_stop(void);
>  
> +/**
> + * device_supports_sysvipc:
> + *
> + * A function to check if the device supports IPC
> + * @return: true or false
> + * */
> +bool device_supports_sysvipc(void);
> +
>  uint64_t intel_allocator_open(int fd, uint32_t ctx, uint8_t allocator_type);
>  uint64_t intel_allocator_open_full(int fd, uint32_t ctx,
>  				   uint64_t start, uint64_t end,
> diff --git a/tests/kms_concurrent.c b/tests/kms_concurrent.c
> index 4f16f8b89..ab9ae29a8 100644
> --- a/tests/kms_concurrent.c
> +++ b/tests/kms_concurrent.c
> @@ -395,8 +395,10 @@ igt_main_args("", long_options, help_str, opt_handler, NULL)
>  		igt_display_require(&data.display, data.drm_fd);
>  		igt_require(data.display.is_atomic);
>  		igt_display_require_output(&data.display);
> +
>  		if (is_intel_device(data.drm_fd))
> -			intel_allocator_multiprocess_start();
> +			igt_require_f(!intel_allocator_multiprocess_start(),
> +							"Allocator failure, no SYSV IPC\n");
>  	}
>  
>  	run_tests_for_pipe(&data);
> -- 
> 2.43.0

-- 
Ville Syrjälä
Intel