drm/radeon: signedness bug in kv_dpm.c

The problem here is that "unsigned i" is always greater than or equal to
zero.  These loops mostly have a second check for "(i == 0)" so only the
last two are actually buggy.  The rest is just cleanup.

Bug 1:  kv_force_dpm_highest() doesn't have an "(i == 0)" check so it's
a potential forever loop.

Bug 2: In kv_get_sleep_divider_id_from_clock() there is a typo and the
test is reversed "<=" vs ">" so we never enter the loop.  That means
normally we return KV_MAX_DEEPSLEEP_DIVIDER_ID (5).  The return value
from here is saved in ->DeepSleepDivId and I wasn't able to determine
how that is used.  This is a static checker fix and I have not tested
it.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/radeon/kv_dpm.c b/drivers/gpu/drm/radeon/kv_dpm.c
index ecd6080..c499daf 100644 (file)
--- a/drivers/gpu/drm/radeon/kv_dpm.c
+++ b/drivers/gpu/drm/radeon/kv_dpm.c
@@ -667,9 +667,8 @@ static int kv_program_bootup_state(struct radeon_device *rdev)
                &rdev->pm.dpm.dyn_state.vddc_dependency_on_sclk;
 
        if (table && table->count) {
-               for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
-                       if ((table->entries[i].clk == pi->boot_pl.sclk) ||
-                           (i == 0))
+               for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+                       if (table->entries[i].clk == pi->boot_pl.sclk)
                                break;
                }
 
@@ -682,9 +681,8 @@ static int kv_program_bootup_state(struct radeon_device *rdev)
                if (table->num_max_dpm_entries == 0)
                        return -EINVAL;
 
-               for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
-                       if ((table->entries[i].sclk_frequency == pi->boot_pl.sclk) ||
-                           (i == 0))
+               for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+                       if (table->entries[i].sclk_frequency == pi->boot_pl.sclk)
                                break;
                }
 
@@ -1588,13 +1586,11 @@ static void kv_set_valid_clock_range(struct radeon_device *rdev,
                        }
                }
 
-               for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
-                       if ((table->entries[i].clk <= new_ps->levels[new_ps->num_levels -1].sclk) ||
-                           (i == 0)) {
-                               pi->highest_valid = i;
+               for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
+                       if (table->entries[i].clk <= new_ps->levels[new_ps->num_levels - 1].sclk)
                                break;
-                       }
                }
+               pi->highest_valid = i;
 
                if (pi->lowest_valid > pi->highest_valid) {
                        if ((new_ps->levels[0].sclk - table->entries[pi->highest_valid].clk) >
@@ -1615,14 +1611,12 @@ static void kv_set_valid_clock_range(struct radeon_device *rdev,
                        }
                }
 
-               for (i = pi->graphics_dpm_level_count - 1; i >= 0; i--) {
+               for (i = pi->graphics_dpm_level_count - 1; i > 0; i--) {
                        if (table->entries[i].sclk_frequency <=
-                           new_ps->levels[new_ps->num_levels - 1].sclk ||
-                           i == 0) {
-                               pi->highest_valid = i;
+                           new_ps->levels[new_ps->num_levels - 1].sclk)
                                break;
-                       }
                }
+               pi->highest_valid = i;
 
                if (pi->lowest_valid > pi->highest_valid) {
                        if ((new_ps->levels[0].sclk -
@@ -1871,7 +1865,7 @@ static int kv_force_dpm_highest(struct radeon_device *rdev)
        if (ret)
                return ret;
 
-       for (i = SMU7_MAX_LEVELS_GRAPHICS - 1; i >= 0; i--) {
+       for (i = SMU7_MAX_LEVELS_GRAPHICS - 1; i > 0; i--) {
                if (enable_mask & (1 << i))
                        break;
        }
@@ -1911,9 +1905,9 @@ static u8 kv_get_sleep_divider_id_from_clock(struct radeon_device *rdev,
        if (!pi->caps_sclk_ds)
                return 0;
 
-       for (i = KV_MAX_DEEPSLEEP_DIVIDER_ID; i <= 0; i--) {
+       for (i = KV_MAX_DEEPSLEEP_DIVIDER_ID; i > 0; i--) {
                temp = sclk / sumo_get_sleep_divider_from_id(i);
-               if ((temp >= min) || (i == 0))
+               if (temp >= min)
                        break;
        }