[PATCH] drm/amd/display: Fix an uninitialized index variable

[PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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;
 
-- 
2.29.2

[PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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;
 
-- 
2.29.2

_______________________________________________
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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

[PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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;
 
-- 
2.29.2

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amd-gfx@lists.freedesktop.org
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Nick Desaulniers]

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
>


-- 
Thanks,
~Nick Desaulniers

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Nick Desaulniers]

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
>


-- 
Thanks,
~Nick Desaulniers
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Nick Desaulniers]

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
>


-- 
Thanks,
~Nick Desaulniers
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Arnd Bergmann]

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
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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
>
> _______________________________________________
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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
>
> _______________________________________________
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> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
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Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH] drm/amd/display: Fix an uninitialized index variable

[Alex Deucher]

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
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
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