Report for unitialized variable warning

Author: varshar16

Report_0003.md

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+# Warning Analysis Report
+
+### General
+
+**Warning Type:** -Wsometimes-uninitialized
+
+**Warning Explanation:**
+```
+drivers/gpu/drm/i915/intel_pm.c:4670:6: warning: variable 'trans_min' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
+        if (INTEL_GEN(dev_priv) >= 10)
+            ^~~~~~~~~~~~~~~~~~~~~~~~~
+drivers/gpu/drm/i915/i915_drv.h:2535:29: note: expanded from macro 'INTEL_GEN'
+#define INTEL_GEN(dev_priv)     ((dev_priv)->info.gen)
+                                ^
+drivers/gpu/drm/i915/intel_pm.c:4673:19: note: uninitialized use occurs here
+        trans_offset_b = trans_min + trans_amount;
+                         ^~~~~~~~~
+drivers/gpu/drm/i915/intel_pm.c:4670:2: note: remove the 'if' if its condition is always true
+        if (INTEL_GEN(dev_priv) >= 10)
+        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+drivers/gpu/drm/i915/intel_pm.c:4655:20: note: initialize the variable 'trans_min' to silence this warning
+        uint16_t trans_min, trans_y_tile_min;
+                          ^
+                           = 0
+```
+### History
+
+**Introduced in version:** v4.15-rc1<br/>
+**Date:** 2017-08-17<br/>
+**Author:** Kumar, Mahesh<br/>
+**Patch:** https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=ca47667f523e588318f89c735e127c256de6cb16
+
+### Warning Assessment
+
+**File Location:** drivers/gpu/drm/i915/intel_pm.c
+
+The variable trans_min is declared in the function<br/>
+skl_compute_transition_wm
+```
+        uint16_t trans_min, trans_y_tile_min;
+```
+This variable is initialized only if the following condition is true.
+```
+        if (INTEL_GEN(dev_priv) >= 10)
+                trans_min = 4;
+```
+The variable is used in two places, one within the if condition and <br/>
+other is outside the condition. The trans_offset_b can have garbage <br/>
+value if the trans_min is not initialized during declaration. <br/>
+```
+        trans_offset_b = trans_min + trans_amount;
+```
+### Conclusion
+
+Clang warning is true in this case.<br/>
+The variable needs to be initialised to zero.<br/>
+
+### Fixed By
+
+**Author:** Chris Wilson<br/>
+**Date:** 2017-11-15<br/>
+**Patch:** https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/i915/intel_pm.c?id=be3fa66857051e2943960a06f8046e8445cdfe6e

Report_0004.md

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+# Warning Analysis Report
+
+### General
+
+**Warning Type:** -Wsometimes-uninitialized
+
+**Warning Explanation:**
+```
+drivers/gpu/drm/i915/intel_crt.c:815:11: warning: variable 'status' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized]
+        else if (ret < 0)
+                 ^~~~~~~
+drivers/gpu/drm/i915/intel_crt.c:820:9: note: uninitialized use occurs here
+        return status;
+               ^~~~~~
+drivers/gpu/drm/i915/intel_crt.c:815:7: note: remove the 'if' if its condition is always true
+        else if (ret < 0)
+             ^~~~~~~~~~~~
+drivers/gpu/drm/i915/intel_crt.c:755:12: note: initialize the variable 'status' to silence this warning
+        int status, ret;
+                  ^
+                   = 0
+```
+### History
+
+**Introduced in version:** v4.12-rc1<br/>
+**Date:** 2017-04-06<br/>
+**Author:** Maarten Lankhorst<br/>
+**Patch:** https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=6c5ed5ae353cdf156f9ac4db17e15db56b4de880
+
+### Warning Assessment
+
+**File Location:** drivers/gpu/drm/i915/intel_pm.c
+
+In the function static int intel_crt_detect,<br/>
+The variable is declared as<br/>
+```
+int status, ret;
+```
+Here the variable status is used within if blocks only. Variable status<br/>
+is always initialized to some value. The else if bock for condition<br/>
+ret < 0 needs to be changed to else block.<br/>
+```
+        ret = intel_get_load_detect_pipe(connector, NULL, &tmp, ctx);
+        if (ret > 0) {
+                if (intel_crt_detect_ddc(connector))
+                        status = connector_status_connected;
+                else if (INTEL_GEN(dev_priv) < 4)
+                        status = intel_crt_load_detect(crt,
+                                to_intel_crtc(connector->state->crtc)->pipe);
+                else if (i915_modparams.load_detect_test)
+                        status = connector_status_disconnected;
+                else
+                        status = connector_status_unknown;
+                intel_release_load_detect_pipe(connector, &tmp, ctx);
+        } else if (ret == 0)
+                status = connector_status_unknown;
+        else if (ret < 0)
+                status = ret;
+```
+### Conclusion
+
+The Clang warning is true in this case too. It suggests two solutions<br/>
+1) remove the 'if' if its condition is always true<br/>
+2) initialize the variable 'status' to silence this warning<br/>
+
+I would prefer solution 1 here, as status is always initialized to some integer value.
+
+### Fixed By
+
+**Author:** Chris Wilson<br/>
+**Date:** 2018-02-08<br/>
+**Patch:** https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/gpu/drm/i915/intel_crt.c?id=2927e4211f76893249cfa8e7ac5fe1c73ae791c1