[Intel-gfx] [bug report] drm/i915/pmu: Use functions common with sysfs to read actual freq

Dan Carpenter error27 at gmail.com
Wed Mar 29 06:24:12 UTC 2023


Hello Ashutosh Dixit,

The patch 12d4eb20d9d8: "drm/i915/pmu: Use functions common with
sysfs to read actual freq" from Mar 15, 2023, leads to the following
Smatch static checker warning:

	drivers/gpu/drm/i915/gt/intel_rps.c:2110 __read_cagf()
	error: uninitialized symbol 'freq'.

drivers/gpu/drm/i915/gt/intel_rps.c
    2082 static u32 __read_cagf(struct intel_rps *rps, bool take_fw)
    2083 {
    2084         struct drm_i915_private *i915 = rps_to_i915(rps);
    2085         struct intel_uncore *uncore = rps_to_uncore(rps);
    2086         i915_reg_t r = INVALID_MMIO_REG;
    2087         u32 freq;
                 ^^^^^^^^

    2088 
    2089         /*
    2090          * For Gen12+ reading freq from HW does not need a forcewake and
    2091          * registers will return 0 freq when GT is in RC6
    2092          */
    2093         if (GRAPHICS_VER_FULL(i915) >= IP_VER(12, 70)) {
    2094                 r = MTL_MIRROR_TARGET_WP1;
    2095         } else if (GRAPHICS_VER(i915) >= 12) {
    2096                 r = GEN12_RPSTAT1;
    2097         } else if (IS_VALLEYVIEW(i915) || IS_CHERRYVIEW(i915)) {
    2098                 vlv_punit_get(i915);
    2099                 freq = vlv_punit_read(i915, PUNIT_REG_GPU_FREQ_STS);
                         ^^^^^^^
Set here.

    2100                 vlv_punit_put(i915);
    2101         } else if (GRAPHICS_VER(i915) >= 6) {
    2102                 r = GEN6_RPSTAT1;
    2103         } else {
    2104                 r = MEMSTAT_ILK;
    2105         }
    2106 
    2107         if (i915_mmio_reg_valid(r))
    2108                 freq = take_fw ? intel_uncore_read(uncore, r) : intel_uncore_read_fw(uncore, r);
                         ^^^^^^
And here...

    2109 
--> 2110         return intel_rps_get_cagf(rps, freq);
                                                ^^^^
Warning.

    2111 }

regards,
dan carpenter


More information about the Intel-gfx mailing list