[bug report] drm/amd/display: Separate setting and programming of cursor

[Dan Carpenter]

Hello Harry Wentland,

Commit f63f86b5affc ("drm/amd/display: Separate setting and
programming of cursor") from Mar 15, 2024 (linux-next), leads to the
following Smatch static checker warning:

	drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c:398 dc_stream_program_cursor_position()
	error: we previously assumed 'stream' could be null (see line 397)

drivers/gpu/drm/amd/amdgpu/../display/dc/core/dc_stream.c
    389 bool dc_stream_program_cursor_position(
    390         struct dc_stream_state *stream,
    391         const struct dc_cursor_position *position)
    392 {
    393         struct dc *dc;
    394         bool reset_idle_optimizations = false;
    395         const struct dc_cursor_position *old_position;
    396 
    397         old_position = stream ? &stream->cursor_position : NULL;
                               ^^^^^^^^
The patch adds a NULL check

--> 398         dc = stream->ctx->dc;
                     ^^^^^^^^
The old code didn't check

    399 
    400         if (dc_stream_set_cursor_position(stream, position)) {
    401                 dc_z10_restore(dc);
    402 
    403                 /* disable idle optimizations if enabling cursor */
    404                 if (dc->idle_optimizations_allowed &&
    405                     (!old_position->enable || dc->debug.exit_idle_opt_for_cursor_updates) &&
    406                     position->enable) {
    407                         dc_allow_idle_optimizations(dc, false);

regards,
dan carpenter