2022-08-26 09:50:43

by sunliming

Subject: [PATCH] drm/amd/display: Fix variable dereferenced before check

Fixes the following smatch warning:

drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:311 dc_dmub_srv_p_state_delegate()
warn: variable dereferenced before check 'dc' (see line 309)

Reported-by: kernel test robot <[email protected]>
Reported-by: Dan Carpenter <[email protected]>
Signed-off-by: sunliming <[email protected]>
---
drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
index 09b304507bad..ebf99e8f93e0 100644
--- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
+++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
@@ -323,11 +323,13 @@ bool dc_dmub_srv_p_state_delegate(struct dc *dc, bool should_manage_pstate, stru
struct dmub_cmd_fw_assisted_mclk_switch_config *config_data = &cmd.fw_assisted_mclk_switch.config_data;
int i = 0;
int ramp_up_num_steps = 1; // TODO: Ramp is currently disabled. Reenable it.
- uint8_t visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
+ uint8_t visual_confirm_enabled;

if (dc == NULL)
return false;

+ visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
+
// Format command.
cmd.fw_assisted_mclk_switch.header.type = DMUB_CMD__FW_ASSISTED_MCLK_SWITCH;
cmd.fw_assisted_mclk_switch.header.sub_type = DMUB_CMD__FAMS_SETUP_FW_CTRL;
--
2.25.1

2022-08-26 21:15:55

by Alex Deucher

Subject: Re: [PATCH] drm/amd/display: Fix variable dereferenced before check

Applied. Thanks!

Alex

On Fri, Aug 26, 2022 at 4:41 AM sunliming <[email protected]> wrote:
>
> Fixes the following smatch warning:
>
> drivers/gpu/drm/amd/amdgpu/../display/dc/dc_dmub_srv.c:311 dc_dmub_srv_p_state_delegate()
> warn: variable dereferenced before check 'dc' (see line 309)
>
> Reported-by: kernel test robot <[email protected]>
> Reported-by: Dan Carpenter <[email protected]>
> Signed-off-by: sunliming <[email protected]>
> ---
> drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
> index 09b304507bad..ebf99e8f93e0 100644
> --- a/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
> +++ b/drivers/gpu/drm/amd/display/dc/dc_dmub_srv.c
> @@ -323,11 +323,13 @@ bool dc_dmub_srv_p_state_delegate(struct dc *dc, bool should_manage_pstate, stru
> struct dmub_cmd_fw_assisted_mclk_switch_config *config_data = &cmd.fw_assisted_mclk_switch.config_data;
> int i = 0;
> int ramp_up_num_steps = 1; // TODO: Ramp is currently disabled. Reenable it.
> - uint8_t visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
> + uint8_t visual_confirm_enabled;
>
> if (dc == NULL)
> return false;
>
> + visual_confirm_enabled = dc->debug.visual_confirm == VISUAL_CONFIRM_FAMS;
> +
> // Format command.
> cmd.fw_assisted_mclk_switch.header.type = DMUB_CMD__FW_ASSISTED_MCLK_SWITCH;
> cmd.fw_assisted_mclk_switch.header.sub_type = DMUB_CMD__FAMS_SETUP_FW_CTRL;
> --
> 2.25.1
>