linux-kernel - [PATCH] drm/i915/gt: Avoid uninitialized use of rpcurupei in frequency

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Date:   Tue, 28 Apr 2020 20:00:52 -0700
From:   Nathan Chancellor <natechancellor@...il.com>
To:     Jani Nikula <jani.nikula@...ux.intel.com>,
        Joonas Lahtinen <joonas.lahtinen@...ux.intel.com>,
        Rodrigo Vivi <rodrigo.vivi@...el.com>,
        Chris Wilson <chris@...is-wilson.co.uk>
Cc:     intel-gfx@...ts.freedesktop.org, dri-devel@...ts.freedesktop.org,
        linux-kernel@...r.kernel.org, clang-built-linux@...glegroups.com,
        Nathan Chancellor <natechancellor@...il.com>
Subject: [PATCH] drm/i915/gt: Avoid uninitialized use of rpcurupei in frequency_show

When building with clang + -Wuninitialized:

drivers/gpu/drm/i915/gt/debugfs_gt_pm.c:407:7: warning: variable
'rpcurupei' is uninitialized when used here [-Wuninitialized]
                           rpcurupei,
                           ^~~~~~~~~
drivers/gpu/drm/i915/gt/debugfs_gt_pm.c:304:16: note: initialize the
variable 'rpcurupei' to silence this warning
                u32 rpcurupei, rpcurup, rpprevup;
                             ^
                              = 0
1 warning generated.

rpupei is assigned twice; based on the second argument to
intel_uncore_read, it seems this one should have been assigned to
rpcurupei.

Fixes: 9c878557b1eb ("drm/i915/gt: Use the RPM config register to determine clk frequencies")
Link: https://github.com/ClangBuiltLinux/linux/issues/1016
Signed-off-by: Nathan Chancellor <natechancellor@...il.com>
---
 drivers/gpu/drm/i915/gt/debugfs_gt_pm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gt/debugfs_gt_pm.c b/drivers/gpu/drm/i915/gt/debugfs_gt_pm.c
index 3d3ef62ed89f..f6ba66206273 100644
--- a/drivers/gpu/drm/i915/gt/debugfs_gt_pm.c
+++ b/drivers/gpu/drm/i915/gt/debugfs_gt_pm.c
@@ -336,7 +336,7 @@ static int frequency_show(struct seq_file *m, void *unused)
 		rpdeclimit = intel_uncore_read(uncore, GEN6_RP_DOWN_THRESHOLD);
 
 		rpstat = intel_uncore_read(uncore, GEN6_RPSTAT1);
-		rpupei = intel_uncore_read(uncore, GEN6_RP_CUR_UP_EI) & GEN6_CURICONT_MASK;
+		rpcurupei = intel_uncore_read(uncore, GEN6_RP_CUR_UP_EI) & GEN6_CURICONT_MASK;
 		rpcurup = intel_uncore_read(uncore, GEN6_RP_CUR_UP) & GEN6_CURBSYTAVG_MASK;
 		rpprevup = intel_uncore_read(uncore, GEN6_RP_PREV_UP) & GEN6_CURBSYTAVG_MASK;
 		rpcurdownei = intel_uncore_read(uncore, GEN6_RP_CUR_DOWN_EI) & GEN6_CURIAVG_MASK;

base-commit: 0fd02a5d3eb7020a7e1801f8d7f01891071c85e4
-- 
2.26.2