Re: [Intel-gfx] [PATCH 03/27] drm/i915/guc: Connect the number of guc_ids to debugfs

John Harrison
2021-09-09T22:16:40Z

On 8/20/2021 15:44, Matthew Brost wrote:
> For testing purposes it may make sense to reduce the number of guc_ids
> available to be allocated. Add debugfs support for setting the number of
> guc_ids.
>
> Signed-off-by: Matthew Brost <matthew.brost@intel.com>
It 'may make sense'? Is there an actual IGT/selftest test that uses this
and needs to in order to not take several hours to run or something?
Seems wrong to be adding a debugfs interface for something that would
only be used for testing by internal developers who can quite easy just
edit a define in the code to simplify their testing.

John.

> ---
> .../gpu/drm/i915/gt/uc/intel_guc_debugfs.c | 31 +++++++++++++++++++
> .../gpu/drm/i915/gt/uc/intel_guc_submission.c | 3 +-
> 2 files changed, 33 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> index 887c8c8f35db..b88d343ee432 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_debugfs.c
> @@ -71,12 +71,43 @@ static bool intel_eval_slpc_support(void *data)
> return intel_guc_slpc_is_used(guc);
> }
>
> +static int guc_num_id_get(void *data, u64 *val)
> +{
> + struct intel_guc *guc = data;
> +
> + if (!intel_guc_submission_is_used(guc))
> + return -ENODEV;
> +
> + *val = guc->num_guc_ids;
> +
> + return 0;
> +}
> +
> +static int guc_num_id_set(void *data, u64 val)
> +{
> + struct intel_guc *guc = data;
> +
> + if (!intel_guc_submission_is_used(guc))
> + return -ENODEV;
> +
> + if (val > guc->max_guc_ids)
> + val = guc->max_guc_ids;
> + else if (val < 256)
> + val = 256;
> +
> + guc->num_guc_ids = val;
> +
> + return 0;
> +}
> +DEFINE_SIMPLE_ATTRIBUTE(guc_num_id_fops, guc_num_id_get, guc_num_id_set, "%lld\n");
> +
> void intel_guc_debugfs_register(struct intel_guc *guc, struct dentry *root)
> {
> static const struct debugfs_gt_file files[] = {
> { "guc_info", &guc_info_fops, NULL },
> { "guc_registered_contexts", &guc_registered_contexts_fops, NULL },
> { "guc_slpc_info", &guc_slpc_info_fops, &intel_eval_slpc_support},
> + { "guc_num_id", &guc_num_id_fops, NULL },
> };
>
> if (!intel_guc_is_supported(guc))
> diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> index 8235e49bb347..68742b612692 100644
> --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
> @@ -2716,7 +2716,8 @@ g2h_context_lookup(struct intel_guc *guc, u32 desc_idx)
>
> if (unlikely(desc_idx >= guc->max_guc_ids)) {
> drm_err(&guc_to_gt(guc)->i915->drm,
> - "Invalid desc_idx %u", desc_idx);
> + "Invalid desc_idx %u, max %u",
> + desc_idx, guc->max_guc_ids);
> return NULL;
> }
>