linux-kernel - [PATCH] drm/i915/display: fix uninitialized variable

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Message-Id: <20200825232057.31601-1-trix@redhat.com>
Date:   Tue, 25 Aug 2020 16:20:57 -0700
From:   trix@...hat.com
To:     jani.nikula@...ux.intel.com, joonas.lahtinen@...ux.intel.com,
        rodrigo.vivi@...el.com, airlied@...ux.ie, daniel@...ll.ch,
        jose.souza@...el.com, matthew.d.roper@...el.com,
        anusha.srivatsa@...el.com, pankaj.laxminarayan.bharadiya@...el.com,
        wambui.karugax@...il.com, vivek.kasireddy@...el.com
Cc:     intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, Tom Rix <trix@...hat.com>
Subject: [PATCH] drm/i915/display: fix uninitialized variable

From: Tom Rix <trix@...hat.com>

clang static analysis flags this error

intel_combo_phy.c:268:7: warning: The left expression of the
  compound assignment is an uninitialized value.
  The computed value will also be garbage
                ret &= check_phy_reg(...
                ~~~ ^

ret has no initial values, in icl_combo_phy_verify_state() ret is
set by the next statment and then updated by similar &= logic.

Because the check_phy_req() are only register reads, reorder the
statements.

Fixes: 239bef676d8e ("drm/i915/display: Implement new combo phy initialization step")
Signed-off-by: Tom Rix <trix@...hat.com>
---
 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..7622ef66c987 100644
--- a/drivers/gpu/drm/i915/display/intel_combo_phy.c
+++ b/drivers/gpu/drm/i915/display/intel_combo_phy.c
@@ -264,6 +264,8 @@ static bool icl_combo_phy_verify_state(struct drm_i915_private *dev_priv,
 	if (!icl_combo_phy_enabled(dev_priv, phy))
 		return false;
 
+	ret = cnl_verify_procmon_ref_values(dev_priv, phy);
+
 	if (INTEL_GEN(dev_priv) >= 12) {
 		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_TX_DW8_LN0(phy),
 				     ICL_PORT_TX_DW8_ODCC_CLK_SEL |
@@ -276,8 +278,6 @@ 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);
-
 	if (phy_is_master(dev_priv, phy)) {
 		ret &= check_phy_reg(dev_priv, phy, ICL_PORT_COMP_DW8(phy),
 				     IREFGEN, IREFGEN);
-- 
2.18.1