[bug report] drm/amd/display: Introduce power module on Linux

[bug report] drm/amd/display: Introduce power module on Linux

[Dan Carpenter]

Hello Ray Wu,

Commit 4cef2ac4c795 ("drm/amd/display: Introduce power module on
Linux") from Feb 27, 2026 (linux-next), leads to the following Smatch
static checker warning:

	drivers/gpu/drm/amd/amdgpu/../display/modules/power/power.c:172 calc_psr_num_static_frames()
	warn: previously used 'vsync_rate_hz' as divisor (see line 163)

drivers/gpu/drm/amd/amdgpu/../display/modules/power/power.c
    158 static unsigned int calc_psr_num_static_frames(unsigned int vsync_rate_hz)
    159 {
    160         /* Calculate number of static frames before generating interrupt to
    161          * enter PSR.
    162          */
    163         unsigned int frame_time_microsec = 1000000 / vsync_rate_hz;
                                                             ^^^^^^^^^^^^^
vsync_rate_hz is used as a divisor here

    164 
    165         // Init fail safe of 2 frames static
    166         unsigned int num_frames_static = 2;
    167 
    168         /* Round up
    169          * Calculate number of frames such that at least 30 ms of time has
    170          * passed.
    171          */
--> 172         if (vsync_rate_hz != 0)
                    ^^^^^^^^^^^^^^^^^^
If it's zero then we already hit a divide by zero bug and crashed.

    173                 num_frames_static = (30000 / frame_time_microsec) + 1;
    174 
    175         return num_frames_static;
    176 }

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regards,
dan carpenter