[PATCH] drm/amd/display: Add 'replay' NULL check in 'edp_set_replay_allow_active()'

[Srinivasan Shanmugam]

In the first if statement, we're checking if 'replay' is NULL. But in
the second if statement, we're not checking if 'replay' is NULL again
before calling replay->funcs->replay_set_power_opt().

if (replay == NULL && force_static)
    return false;

...

if (link->replay_settings.replay_feature_enabled &&
    replay->funcs->replay_set_power_opt) {
        replay->funcs->replay_set_power_opt(replay, *power_opts, panel_inst);
        link->replay_settings.replay_power_opt_active = *power_opts;
}

If 'replay' is NULL, this will cause a null pointer dereference.

Fixes the below found by smatch:
drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:895
 edp_set_replay_allow_active() error: we previously assumed 'replay' could be 
null (see line 887)

Fixes: c7ddc0a800bc ("drm/amd/display: Add Functions to enable Freesync Panel 
Replay")
Cc: Bhawanpreet Lakha <bhawanpreet.la...@amd.com>
Cc: Roman Li <roman...@amd.com>
Cc: Rodrigo Siqueira <rodrigo.sique...@amd.com>
Cc: Aurabindo Pillai <aurabindo.pil...@amd.com>
Cc: Tom Chung <chiahsuan.ch...@amd.com>
Suggested-by: Tom Chung <chiahsuan.ch...@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmu...@amd.com>
---
 .../drm/amd/display/dc/link/protocols/link_edp_panel_control.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git 
a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c 
b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
index 443215b96308..acfbbc638cc6 100644
--- a/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
+++ b/drivers/gpu/drm/amd/display/dc/link/protocols/link_edp_panel_control.c
@@ -892,7 +892,8 @@ bool edp_set_replay_allow_active(struct dc_link *link, 
const bool *allow_active,
 
        /* Set power optimization flag */
        if (power_opts && link->replay_settings.replay_power_opt_active != 
*power_opts) {
-               if (link->replay_settings.replay_feature_enabled && 
replay->funcs->replay_set_power_opt) {
+               if (replay != NULL && 
link->replay_settings.replay_feature_enabled &&
+                   replay->funcs->replay_set_power_opt) {
                        replay->funcs->replay_set_power_opt(replay, 
*power_opts, panel_inst);
                        link->replay_settings.replay_power_opt_active = 
*power_opts;
                }
-- 
2.34.1