drm/i915: Fix -Wstringop-overflow warning in call to intel_read_wm_latency()

Fix the following -Wstringop-overflow warnings when building with GCC-11:

drivers/gpu/drm/i915/intel_pm.c:3106:9: warning: ‘intel_read_wm_latency’ accessing 16 bytes in a region of size 10 [-Wstringop-overflow=]
 3106 |         intel_read_wm_latency(dev_priv, dev_priv->wm.pri_latency);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
drivers/gpu/drm/i915/intel_pm.c:3106:9: note: referencing argument 2 of type ‘u16 *’ {aka ‘short unsigned int *’}
drivers/gpu/drm/i915/intel_pm.c:2861:13: note: in a call to function ‘intel_read_wm_latency’
 2861 | static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
      |             ^~~~~~~~~~~~~~~~~~~~~

by removing the over-specified array size from the argument declarations.

It seems that this code is actually safe because the size of the
array depends on the hardware generation, and the function checks
for that.

Notice that wm can be an array of 5 elements:
drivers/gpu/drm/i915/intel_pm.c:3109:   intel_read_wm_latency(dev_priv, dev_priv->wm.pri_latency);

or an array of 8 elements:
drivers/gpu/drm/i915/intel_pm.c:3131:   intel_read_wm_latency(dev_priv, dev_priv->wm.skl_latency);

and the compiler legitimately complains about that.

This helps with the ongoing efforts to globally enable
-Wstringop-overflow.

Link: https://github.com/KSPP/linux/issues/181
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 9333f732cda8e7cc3f21da9694182e248b7e1a4f..5167d63010b9926fb8506bca157b7995780b77db 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -2859,7 +2859,7 @@ static void ilk_compute_wm_level(const struct drm_i915_private *dev_priv,
 }
 
 static void intel_read_wm_latency(struct drm_i915_private *dev_priv,
-                                 u16 wm[8])
+                                 u16 wm[])
 {
        struct intel_uncore *uncore = &dev_priv->uncore;