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From: Nathan Chancellor <>
To: Jani Nikula <>,
	Joonas Lahtinen <>,
	Rodrigo Vivi <>
Cc: "José Roberto de Souza" <>,
	"Matt Roper" <>,,,,,
	"Nathan Chancellor" <>
Subject: [PATCH] drm/i915/display: Ensure that ret is always initialized in icl_combo_phy_verify_state
Date: Wed, 15 Jul 2020 21:27:42 -0700	[thread overview]
Message-ID: <> (raw)

Clang warns:

drivers/gpu/drm/i915/display/intel_combo_phy.c:268:3: warning: variable
'ret' is uninitialized when used here [-Wuninitialized]
                ret &= check_phy_reg(dev_priv, phy, ICL_PORT_TX_DW8_LN0(phy),
drivers/gpu/drm/i915/display/intel_combo_phy.c:261:10: note: initialize
the variable 'ret' to silence this warning
        bool ret;
                 = 0
1 warning generated.

In practice, the bug this warning appears to be concerned with would not
actually matter because ret gets initialized to the return value of
cnl_verify_procmon_ref_values. However, that does appear to be a bug
since it means the first hunk of the patch this fixes won't actually do
anything (since the values of check_phy_reg won't factor into the final
ret value). Initialize ret to true then make all of the assignments a
bitwise AND with itself so that the function always does what it should

Fixes: 239bef676d8e ("drm/i915/display: Implement new combo phy initialization step")
Signed-off-by: Nathan Chancellor <>
 drivers/gpu/drm/i915/display/intel_combo_phy.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/i915/display/intel_combo_phy.c b/drivers/gpu/drm/i915/display/intel_combo_phy.c
index eccaa79cb4a9..a4b8aa6d0a9e 100644
--- a/drivers/gpu/drm/i915/display/intel_combo_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_combo_phy.c
@@ -258,7 +258,7 @@ static bool phy_is_master(struct drm_i915_private *dev_priv, enum phy phy)
 static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
 				       enum phy phy)
-	bool ret;
+	bool ret = true;
 	u32 expected_val = 0;
 	if (!icl_combo_phy_enabled(dev_priv, phy))
@@ -276,7 +276,7 @@ static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
-	ret = cnl_verify_procmon_ref_values(dev_priv, phy);
+	ret &= cnl_verify_procmon_ref_values(dev_priv, phy);
 	if (phy_is_master(dev_priv, phy)) {
 		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_COMP_DW8(phy),

base-commit: ca0e494af5edb59002665bf12871e94b4163a257

             reply	other threads:[~2020-07-16  4:28 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-16  4:27 Nathan Chancellor [this message]
2020-07-16  5:31 ` Matt Roper

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