drm/amd/pm: a quick fix for "divided by zero" error

Considering Arcturus is a dedicated ASIC for computing, it
will be more proper to drop the support for fan speed reading
and setting. That's on the TODO list.

Signed-off-by: Evan Quan <evan.quan@amd.com>
Reported-by: Rui Teng <rui.teng@amd.com>
Reviewed-by: Guchun Chen <guchun.chen@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
index fbf71fc..273df66 100644 (file)
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
@@ -1227,8 +1227,12 @@ static int arcturus_get_fan_speed_rpm(struct smu_context *smu,
 
                tmp64 = (uint64_t)crystal_clock_freq * 60 * 10000;
                tach_status = RREG32_SOC15(THM, 0, mmCG_TACH_STATUS_ARCT);
-               do_div(tmp64, tach_status);
-               *speed = (uint32_t)tmp64;
+               if (tach_status) {
+                       do_div(tmp64, tach_status);
+                       *speed = (uint32_t)tmp64;
+               } else {
+                       *speed = 0;
+               }
 
                break;
        }
@@ -1303,12 +1307,14 @@ static int arcturus_get_fan_speed_pwm(struct smu_context *smu,
                                CG_FDO_CTRL1, FMAX_DUTY100);
        duty = REG_GET_FIELD(RREG32_SOC15(THM, 0, mmCG_THERMAL_STATUS_ARCT),
                                CG_THERMAL_STATUS, FDO_PWM_DUTY);
-       if (!duty100)
-               return -EINVAL;
 
-       tmp64 = (uint64_t)duty * 255;
-       do_div(tmp64, duty100);
-       *speed = MIN((uint32_t)tmp64, 255);
+       if (duty100) {
+               tmp64 = (uint64_t)duty * 255;
+               do_div(tmp64, duty100);
+               *speed = MIN((uint32_t)tmp64, 255);
+       } else {
+               *speed = 0;
+       }
 
        return 0;
 }

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
index 01b9653..87b0554 100644 (file)
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
@@ -1306,8 +1306,13 @@ int smu_v11_0_get_fan_speed_rpm(struct smu_context *smu,
        tmp64 = (uint64_t)crystal_clock_freq * 60 * 10000;
 
        tach_status = RREG32_SOC15(THM, 0, mmCG_TACH_STATUS);
-       do_div(tmp64, tach_status);
-       *speed = (uint32_t)tmp64;
+       if (tach_status) {
+               do_div(tmp64, tach_status);
+               *speed = (uint32_t)tmp64;
+       } else {
+               dev_warn_once(adev->dev, "Got zero output on CG_TACH_STATUS reading!\n");
+               *speed = 0;
+       }
 
        return 0;
 }