From b79ffa914ede785a721f42d8ee3ce7b8eeede2bb Mon Sep 17 00:00:00 2001
From: Chris Wilson <chris@chris-wilson.co.uk>
Date: Wed, 16 Sep 2020 11:50:21 +0100
Subject: [PATCH] drm/i915: Initialise outparam for error return from
wait_for_register
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Just in case the caller passes in 0 for both slow&fast timeouts, make
sure we initialise the stack value returned. Add an assert so that we
don't make the mistake of passing 0 timeouts for the wait.
drivers/gpu/drm/i915/intel_uncore.c:2011 __intel_wait_for_register_fw() error: uninitialized symbol 'reg_value'.
References: 3f649ab728cd ("treewide: Remove uninitialized_var() usage")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: José Roberto de Souza <jose.souza@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200916105022.28316-1-chris@chris-wilson.co.uk
---
drivers/gpu/drm/i915/intel_uncore.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
index 8d5a933e6af60..263ffcb832b79 100644
--- a/drivers/gpu/drm/i915/intel_uncore.c
+++ b/drivers/gpu/drm/i915/intel_uncore.c
@@ -1993,13 +1993,14 @@ int __intel_wait_for_register_fw(struct intel_uncore *uncore,
unsigned int slow_timeout_ms,
u32 *out_value)
{
- u32 reg_value;
+ u32 reg_value = 0;
#define done (((reg_value = intel_uncore_read_fw(uncore, reg)) & mask) == value)
int ret;
/* Catch any overuse of this function */
might_sleep_if(slow_timeout_ms);
GEM_BUG_ON(fast_timeout_us > 20000);
+ GEM_BUG_ON(!fast_timeout_us && !slow_timeout_ms);
ret = -ETIMEDOUT;
if (fast_timeout_us && fast_timeout_us <= 20000)