From 6baa2e0c8ab89664285bb0780bfd39276bc27a88 Mon Sep 17 00:00:00 2001 From: Nathan Chancellor Date: Fri, 28 Aug 2020 13:28:30 -0700 Subject: [PATCH] drm/i915/display: Ensure that ret is always initialized in icl_combo_phy_verify_state MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit 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 do. Fixes: 239bef676d8e ("drm/i915/display: Implement new combo phy initialization step") Link: https://github.com/ClangBuiltLinux/linux/issues/1094 Signed-off-by: Nathan Chancellor Reviewed-by: Matt Roper Link: https://patchwork.freedesktop.org/patch/msgid/20200828202830.7165-1-jose.souza@intel.com Signed-off-by: José Roberto de Souza (cherry picked from commit 2034c2129bc4a91d471815d4dc7a2a69eaa5338d) Signed-off-by: Jani Nikula --- 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 6968de4f3477..157d8c8c605a 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, DCC_MODE_SELECT_CONTINUOSLY); } - 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),