From: Arnd Bergmann arnd@arndb.de
clang points out that the new logic uses an always-uninitialized array index:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9810:38: warning: variable 'i' is uninitialized when used here [-Wuninitialized] timing = &edid->detailed_timings[i]; ^ drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9720:7: note: initialize the variable 'i' to silence this warning
My best guess is that the index should have been returned by the parse_hdmi_amd_vsdb() function that walks an array here, so do that.
Fixes: f9b4f20c4777 ("drm/amd/display: Add Freesync HDMI support to DM") Signed-off-by: Arnd Bergmann arnd@arndb.de --- .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 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 b19b93c74bae..667c0d52dbfa 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -9736,7 +9736,7 @@ static bool parse_edid_cea(struct amdgpu_dm_connector *aconnector, return false; }
-static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, +static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info) { uint8_t *edid_ext = NULL; @@ -9746,7 +9746,7 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, /*----- drm_find_cea_extension() -----*/ /* No EDID or EDID extensions */ if (edid == NULL || edid->extensions == 0) - return false; + return -ENODEV;
/* Find CEA extension */ for (i = 0; i < edid->extensions; i++) { @@ -9756,14 +9756,15 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, }
if (i == edid->extensions) - return false; + return -ENODEV;
/*----- cea_db_offsets() -----*/ if (edid_ext[0] != CEA_EXT) - return false; + return -ENODEV;
valid_vsdb_found = parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info); - return valid_vsdb_found; + + return valid_vsdb_found ? i : -ENODEV; }
void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, @@ -9781,7 +9782,6 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, struct amdgpu_device *adev = drm_to_adev(dev); bool freesync_capable = false; struct amdgpu_hdmi_vsdb_info vsdb_info = {0}; - bool hdmi_valid_vsdb_found = false;
if (!connector->state) { DRM_ERROR("%s - Connector has no state", __func__); @@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, } } } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) { - hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info); - if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) { + i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info); + if (i >= 0 && vsdb_info.freesync_supported) { timing = &edid->detailed_timings[i]; data = &timing->data.other_data;
On Thu, Feb 25, 2021 at 7:01 AM Arnd Bergmann arnd@kernel.org wrote:
From: Arnd Bergmann arnd@arndb.de
clang points out that the new logic uses an always-uninitialized array index:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9810:38: warning: variable 'i' is uninitialized when used here [-Wuninitialized] timing = &edid->detailed_timings[i]; ^ drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9720:7: note: initialize the variable 'i' to silence this warning
My best guess is that the index should have been returned by the parse_hdmi_amd_vsdb() function that walks an array here, so do that.
Fixes: f9b4f20c4777 ("drm/amd/display: Add Freesync HDMI support to DM") Signed-off-by: Arnd Bergmann arnd@arndb.de
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 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 b19b93c74bae..667c0d52dbfa 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -9736,7 +9736,7 @@ static bool parse_edid_cea(struct amdgpu_dm_connector *aconnector, return false; }
-static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, +static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info) { uint8_t *edid_ext = NULL; @@ -9746,7 +9746,7 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, /*----- drm_find_cea_extension() -----*/ /* No EDID or EDID extensions */ if (edid == NULL || edid->extensions == 0)
return false;
return -ENODEV; /* Find CEA extension */ for (i = 0; i < edid->extensions; i++) {@@ -9756,14 +9756,15 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, }
if (i == edid->extensions)
return false;
return -ENODEV; /*----- cea_db_offsets() -----*/ if (edid_ext[0] != CEA_EXT)
return false;
return -ENODEV; valid_vsdb_found = parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info);
return valid_vsdb_found;
return valid_vsdb_found ? i : -ENODEV;
Thanks for the patch!
I don't think we need a local variable to store the return value from one function call that's immediately returned, ie.
return parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info) ? i : -ENODEV;
would suffice, but the patch is still fine as is.
Reviewed-by: Nick Desaulniers ndesaulniers@google.com
}
void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, @@ -9781,7 +9782,6 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, struct amdgpu_device *adev = drm_to_adev(dev); bool freesync_capable = false; struct amdgpu_hdmi_vsdb_info vsdb_info = {0};
bool hdmi_valid_vsdb_found = false; if (!connector->state) { DRM_ERROR("%s - Connector has no state", __func__);@@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, } } } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) {
i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (i >= 0 && vsdb_info.freesync_supported) {
reusing `i` here is safe, for now, but reuse of variables like this in separate branches like this might not get noticed if the function is amended in the future.
timing = &edid->detailed_timings[i]; data = &timing->data.other_data;-- 2.29.2
On Thu, Feb 25, 2021 at 10:34 PM 'Nick Desaulniers' via Clang Built Linux clang-built-linux@googlegroups.com wrote:
return parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info) ? i : -ENODEV;
would suffice, but the patch is still fine as is.
Right, I did not want to change more than necessary here, and the original code already had the extra assignment instead of returning the value.
@@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, } } } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) {
i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (i >= 0 && vsdb_info.freesync_supported) {reusing `i` here is safe, for now, but reuse of variables like this in separate branches like this might not get noticed if the function is amended in the future.
timing = &edid->detailed_timings[i]; data = &timing->data.other_data;
The entire point of the patch is that 'i' is in fact used in the following line, but was lacking an intialization.
Arnd
On Thu, Feb 25, 2021 at 10:01 AM Arnd Bergmann arnd@kernel.org wrote:
From: Arnd Bergmann arnd@arndb.de
clang points out that the new logic uses an always-uninitialized array index:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9810:38: warning: variable 'i' is uninitialized when used here [-Wuninitialized] timing = &edid->detailed_timings[i]; ^ drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9720:7: note: initialize the variable 'i' to silence this warning
My best guess is that the index should have been returned by the parse_hdmi_amd_vsdb() function that walks an array here, so do that.
Fixes: f9b4f20c4777 ("drm/amd/display: Add Freesync HDMI support to DM") Signed-off-by: Arnd Bergmann arnd@arndb.de
This looks correct to me. Stylon can you verify?
Thanks,
Alex
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 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 b19b93c74bae..667c0d52dbfa 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -9736,7 +9736,7 @@ static bool parse_edid_cea(struct amdgpu_dm_connector *aconnector, return false; }
-static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, +static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info) { uint8_t *edid_ext = NULL; @@ -9746,7 +9746,7 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, /*----- drm_find_cea_extension() -----*/ /* No EDID or EDID extensions */ if (edid == NULL || edid->extensions == 0)
return false;
return -ENODEV; /* Find CEA extension */ for (i = 0; i < edid->extensions; i++) {@@ -9756,14 +9756,15 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, }
if (i == edid->extensions)
return false;
return -ENODEV; /*----- cea_db_offsets() -----*/ if (edid_ext[0] != CEA_EXT)
return false;
return -ENODEV; valid_vsdb_found = parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info);
return valid_vsdb_found;
return valid_vsdb_found ? i : -ENODEV;}
void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, @@ -9781,7 +9782,6 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, struct amdgpu_device *adev = drm_to_adev(dev); bool freesync_capable = false; struct amdgpu_hdmi_vsdb_info vsdb_info = {0};
bool hdmi_valid_vsdb_found = false; if (!connector->state) { DRM_ERROR("%s - Connector has no state", __func__);@@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, } } } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) {
i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (i >= 0 && vsdb_info.freesync_supported) { timing = &edid->detailed_timings[i]; data = &timing->data.other_data;-- 2.29.2
dri-devel mailing list dri-devel@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/dri-devel
On Thu, Feb 25, 2021 at 10:01 AM Arnd Bergmann arnd@kernel.org wrote:
From: Arnd Bergmann arnd@arndb.de
clang points out that the new logic uses an always-uninitialized array index:
drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9810:38: warning: variable 'i' is uninitialized when used here [-Wuninitialized] timing = &edid->detailed_timings[i]; ^ drivers/gpu/drm/amd/amdgpu/../display/amdgpu_dm/amdgpu_dm.c:9720:7: note: initialize the variable 'i' to silence this warning
My best guess is that the index should have been returned by the parse_hdmi_amd_vsdb() function that walks an array here, so do that.
Fixes: f9b4f20c4777 ("drm/amd/display: Add Freesync HDMI support to DM") Signed-off-by: Arnd Bergmann arnd@arndb.de
Applied. Thanks!
Alex
.../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 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 b19b93c74bae..667c0d52dbfa 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -9736,7 +9736,7 @@ static bool parse_edid_cea(struct amdgpu_dm_connector *aconnector, return false; }
-static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, +static int parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, struct edid *edid, struct amdgpu_hdmi_vsdb_info *vsdb_info) { uint8_t *edid_ext = NULL; @@ -9746,7 +9746,7 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, /*----- drm_find_cea_extension() -----*/ /* No EDID or EDID extensions */ if (edid == NULL || edid->extensions == 0)
return false;
return -ENODEV; /* Find CEA extension */ for (i = 0; i < edid->extensions; i++) {@@ -9756,14 +9756,15 @@ static bool parse_hdmi_amd_vsdb(struct amdgpu_dm_connector *aconnector, }
if (i == edid->extensions)
return false;
return -ENODEV; /*----- cea_db_offsets() -----*/ if (edid_ext[0] != CEA_EXT)
return false;
return -ENODEV; valid_vsdb_found = parse_edid_cea(aconnector, edid_ext, EDID_LENGTH, vsdb_info);
return valid_vsdb_found;
return valid_vsdb_found ? i : -ENODEV;}
void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, @@ -9781,7 +9782,6 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, struct amdgpu_device *adev = drm_to_adev(dev); bool freesync_capable = false; struct amdgpu_hdmi_vsdb_info vsdb_info = {0};
bool hdmi_valid_vsdb_found = false; if (!connector->state) { DRM_ERROR("%s - Connector has no state", __func__);@@ -9857,8 +9857,8 @@ void amdgpu_dm_update_freesync_caps(struct drm_connector *connector, } } } else if (edid && amdgpu_dm_connector->dc_sink->sink_signal == SIGNAL_TYPE_HDMI_TYPE_A) {
hdmi_valid_vsdb_found = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (hdmi_valid_vsdb_found && vsdb_info.freesync_supported) {
i = parse_hdmi_amd_vsdb(amdgpu_dm_connector, edid, &vsdb_info);if (i >= 0 && vsdb_info.freesync_supported) { timing = &edid->detailed_timings[i]; data = &timing->data.other_data;-- 2.29.2
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