archive mirror
 help / color / mirror / Atom feed
From: Nathan Chancellor <>
To: Zhenyu Wang <>,
	Zhi Wang <>,
	Jani Nikula <>,
	Joonas Lahtinen <>,
	Rodrigo Vivi <>
	Nathan Chancellor <>
Subject: [PATCH] drm/i915: Mark check_shadow_context_ppgtt as maybe unused
Date: Fri, 15 May 2020 19:35:45 -0700	[thread overview]
Message-ID: <> (raw)

When CONFIG_DRM_I915_DEBUG_GEM is not set, clang warns:

drivers/gpu/drm/i915/gvt/scheduler.c:884:1: warning: function
'check_shadow_context_ppgtt' is not needed and will not be emitted
check_shadow_context_ppgtt(struct execlist_ring_context *c, struct
intel_vgpu_mm *m)
1 warning generated.

This warning is similar to -Wunused-function but rather than warning
that the function is completely unused, it warns that it is used in some
expression within the file but that expression will be evaluated to a
constant or be optimized away in the final assembly, essentially making
it appeared used but really isn't. Usually, this happens when a function
or variable is only used in sizeof, where it will appear to be used but
will be evaluated at compile time and not be required to be emitted.

In this case, the function is only used in GEM_BUG_ON, which is defined
as BUILD_BUG_ON_INVALID, which intentionally follows this pattern. To
fix this warning, add __maybe_unused to make it clear that this is
intentional depending on the configuration.

Fixes: bec3df930fbd ("drm/i915/gvt: Support PPGTT table load command")
Signed-off-by: Nathan Chancellor <>
 drivers/gpu/drm/i915/gvt/scheduler.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gvt/scheduler.c b/drivers/gpu/drm/i915/gvt/scheduler.c
index f776c92de8d7..0fb1df71c637 100644
--- a/drivers/gpu/drm/i915/gvt/scheduler.c
+++ b/drivers/gpu/drm/i915/gvt/scheduler.c
@@ -880,7 +880,7 @@ static void update_guest_pdps(struct intel_vgpu *vgpu,
 				gpa + i * 8, &pdp[7 - i], 4);
-static bool
+static __maybe_unused bool
 check_shadow_context_ppgtt(struct execlist_ring_context *c, struct intel_vgpu_mm *m)
 	if (m->ppgtt_mm.root_entry_type == GTT_TYPE_PPGTT_ROOT_L4_ENTRY) {

base-commit: bdecf38f228bcca73b31ada98b5b7ba1215eb9c9

             reply	other threads:[~2020-05-16  2:36 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-16  2:35 Nathan Chancellor [this message]
2020-05-18  6:09 ` Zhenyu Wang

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \ \ \ \ \ \ \ \ \ \ \ \ \
    --subject='Re: [PATCH] drm/i915: Mark check_shadow_context_ppgtt as maybe unused' \

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
on how to clone and mirror all data and code used for this inbox