Re: [PATCH i-g-t v4] tests/xe_debugfs: add uc debugfs validation and read tests

On 7/22/2026 9:02 AM, root wrote:
> From: Sobin Thomas <[email protected]>
>
> Add coverage for GT-specific uc debugfs entries by introducing a new
> uc-info-read subtest that validates the presence of required files in the
> GT debugfs hierarchy. The test currently verifies the existence of
> the following debugfs nodes:
>
>    - uc/gsc_info
>    - uc/huc_info
>    - uc/guc_info
>    - uc/guc_pc
>
> These additions improve validation of Xe GT debugfs interfaces and
> provide basic functional coverage for the GSC information debugfs node.
>
> v2: Add support for guc and huc info (Daniele)
> v3: Added checks for the device nodes.
> v4: Consolidated the calls into single test_uc_info_read subtest
>
> Signed-off-by: Sobin Thomas <[email protected]>
> ---
>   tests/intel/xe_debugfs.c | 73 +++++++++++++++++++++++++++++++++++++++-
>   1 file changed, 72 insertions(+), 1 deletion(-)
>
> diff --git a/tests/intel/xe_debugfs.c b/tests/intel/xe_debugfs.c
> index da482157e..fd651801c 100644
> --- a/tests/intel/xe_debugfs.c
> +++ b/tests/intel/xe_debugfs.c
> @@ -16,6 +16,18 @@ struct {
>   	bool warn_on_not_hit;
>   } opt = { 0 };
>   
> +struct uc_info_node {
> +	const char *node;
> +	bool mandatory;
> +};
> +
> +static const struct uc_info_node uc_info_nodes[] = {
> +	{ "uc/gsc_info", false },
> +	{ "uc/huc_info", false },
> +	{ "uc/guc_info", true },
> +	{ "uc/guc_pc",   true },
> +};
> +
>   /**
>    * TEST: Xe debugfs test
>    * Description: Xe-specific debugfs tests. These are complementary to the
> @@ -595,6 +607,58 @@ static void check_gt_reg_sr(int fd, int gt)
>   	igt_assert_eq(problems, 0);
>   }
>   
> +/**
> + * SUBTEST: uc-info-read
> + * Description: This is for reading the uc device nodes.
> + */
> +static void test_uc_info_read(struct xe_device *xe_dev, unsigned int gt)
> +{
> +	int debugfs_fd = igt_debugfs_gt_dir(xe_dev->fd, gt);
> +	int i;
> +	int fail_count = 0;
> +
> +	igt_skip_on_f(debugfs_fd < 0, "Failed to open debugfs directory\n");
> +
> +	for (i = 0; i < ARRAY_SIZE(uc_info_nodes); i++) {
> +		const char *node = uc_info_nodes[i].node;
> +		bool mandatory = uc_info_nodes[i].mandatory;
> +		char *buf;
> +
> +		if (faccessat(debugfs_fd, node, F_OK, 0) < 0) {

We do have the igt_sysfs_has_attr helper that already wraps the 
faccessat check.

> +			if (mandatory)
> +				fail_count++;
> +			igt_info("%s debugfs node not present on GT-%u\n", node, gt);
> +			continue;
> +		}
> +		buf = igt_sysfs_get(debugfs_fd, node);
> +		if (!buf) {
> +			if (mandatory) {
> +				fail_count++;
> +				igt_info("Failed to read mandatory %s debugfs file on GT-%u\n",
> +					 node, gt);
> +			} else {
> +				igt_info("Failed to read %s debugfs file on GT-%u\n", node, gt);

Here you have separate logs for mandatory vs optional, but above for the 
missing node you don't. my personal preference goes to having a single 
log statement, if you want to have the "mandatory" or "optional" words 
in it you can just pass them as a sting param based on the value of the 
mandatory variable.

> +			}
> +			continue;
> +		}
> +		if (buf[0] == '\0') {
> +			free(buf);
> +			if (mandatory) {
> +				fail_count++;
> +				igt_info("Mandatory %s debugfs file is empty on GT-%u\n", node, gt);
> +			} else {
> +				igt_info("Optional %s debugfs file is empty on GT-%u\n", node, gt);
> +			}
> +			continue;
> +		}
> +		igt_info("GT-%u: successfully read %s (%zu bytes)\n", gt, node, strlen(buf));
> +		free(buf);

Could use some empty lines between the if statements to make the code 
more readable.

Daniele

> +	}
> +	close(debugfs_fd);
> +	igt_fail_on_f(fail_count > 0, "%d mandatory debugfs node(s) failed  (missing/unreadable/empty) on GT-%u\n",
> +		      fail_count, gt);
> +}
> +
>   const char *help_str =
>   	"  --warn-not-hit|--w\tWarn about devfs nodes that have no tests";
>   
> @@ -619,8 +683,9 @@ static int opt_handler(int option, int option_index, void *input)
>   int igt_main_args("", long_options, help_str, opt_handler, NULL)
>   {
>   	struct xe_device *xe_dev;
> +	int fd = -1;
> +	unsigned int gt;
>   	unsigned int t;
> -	int fd = -1, gt;
>   
>   	igt_fixture() {
>   		fd = drm_open_driver_master(DRIVER_XE);
> @@ -648,6 +713,12 @@ int igt_main_args("", long_options, help_str, opt_handler, NULL)
>   			igt_dynamic_f("gt%d", gt)
>   				check_gt_reg_sr(fd, gt);
>   
> +	igt_describe("Verify that uC debugfs info nodes are present and readable.");
> +	igt_subtest_with_dynamic("uc-info-read")
> +		xe_for_each_gt(fd, gt)
> +			igt_dynamic_f("gt%d", gt)
> +				test_uc_info_read(xe_dev, gt);
> +
>   	igt_fixture() {
>   		drm_close_driver(fd);
>   	}