[PATCH 2/3] drm/amd/pm: fix the Out-of-bounds read warning

[Jesse Zhang]

using index i - 1U may beyond element index
for mc_data[] when i = 0.

Signed-off-by: Jesse Zhang <jesse.zh...@amd.com>
---
 drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c 
b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c
index b1b4c09c3467..b56298d9da98 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/ppatomctrl.c
@@ -73,8 +73,9 @@ static int atomctrl_retrieve_ac_timing(
                                        j++;
                                } else if 
((table->mc_reg_address[i].uc_pre_reg_data &
                                                        LOW_NIBBLE_MASK) == 
DATA_EQU_PREV) {
-                                       
table->mc_reg_table_entry[num_ranges].mc_data[i] =
-                                               
table->mc_reg_table_entry[num_ranges].mc_data[i-1];
+                                       if (i)
+                                               
table->mc_reg_table_entry[num_ranges].mc_data[i] =
+                                                       
table->mc_reg_table_entry[num_ranges].mc_data[i-1];
                                }
                        }
                        num_ranges++;
-- 
2.25.1