The function dereferences amdgpu_dm_connector->dc_link early to
initialize verified_link_cap and dc, but later still checks
amdgpu_dm_connector->dc_link for NULL in the analog path.
This late NULL check is redundant, introduce a local dc_link pointer,
use it consistently, and drop the superfluous NULL check while using
dc_link->link_id.id instead.
The function uses dc_link at the very beginning without checking if it
is NULL. But later in the code, it suddenly checks if dc_link is NULL.
This check is too late to be useful, because the code has already used
dc_link earlier. So this NULL check does nothing.
We simplify the code by storing amdgpu_dm_connector->dc_link in a local
dc_link variable and using it throughout the function. Since dc_link is
already dereferenced early, the later NULL check is unnecessary and is
removed.
Fixes the below:
amdgpu_dm_connector_get_modes():
variable dereferenced before check 'amdgpu_dm_connector->dc_link'
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c
8845
&amdgpu_dm_connector->dc_link->verified_link_cap;
8846 const struct dc *dc = amdgpu_dm_connector->dc_link->dc;
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Dereference
...
8856
8857 if (amdgpu_dm_connector->dc_sink &&
8858 amdgpu_dm_connector->dc_link &&
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Checked too late.
Presumably this NULL check could be removed?
...
Fixes: c8f52ca2cefb ("drm/amd/display: Cleanup uses of the analog flag")
Reported by: Dan Carpenter <[email protected]>
Cc: Timur Kristóf <[email protected]>
Cc: Aurabindo Pillai <[email protected]>
Cc: Roman Li <[email protected]>
Cc: Harry Wentland <[email protected]>
Cc: Tom Chung <[email protected]>
Signed-off-by: Srinivasan Shanmugam <[email protected]>
---
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 8a0555365719..6eb88a96cc33 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -8818,11 +8818,11 @@ static int amdgpu_dm_connector_get_modes(struct
drm_connector *connector)
{
struct amdgpu_dm_connector *amdgpu_dm_connector =
to_amdgpu_dm_connector(connector);
+ struct dc_link *dc_link = amdgpu_dm_connector->dc_link;
struct drm_encoder *encoder;
const struct drm_edid *drm_edid = amdgpu_dm_connector->drm_edid;
- struct dc_link_settings *verified_link_cap =
- &amdgpu_dm_connector->dc_link->verified_link_cap;
- const struct dc *dc = amdgpu_dm_connector->dc_link->dc;
+ struct dc_link_settings *verified_link_cap =
&dc_link->verified_link_cap;
+ const struct dc *dc = dc_link->dc;
encoder = amdgpu_dm_connector_to_encoder(connector);
@@ -8834,9 +8834,8 @@ static int amdgpu_dm_connector_get_modes(struct
drm_connector *connector)
drm_add_modes_noedid(connector, 1920, 1080);
if (amdgpu_dm_connector->dc_sink &&
- amdgpu_dm_connector->dc_link &&
amdgpu_dm_connector->dc_sink->edid_caps.analog &&
-
dc_connector_supports_analog(amdgpu_dm_connector->dc_link->link_id.id)) {
+ dc_connector_supports_analog(dc_link->link_id.id)) {
/* Analog monitor connected by DAC load detection.
* Add common modes. It will be up to the user to
select one that works.
*/
--
2.34.1
