[bug report] drm/amd/display: Refactor panel replay set dmub cmd flow

[bug report] drm/amd/display: Refactor panel replay set dmub cmd flow

[Dan Carpenter]

Hello Jack Chang,

Commit 74ce00932e7e ("drm/amd/display: Refactor panel replay set dmub
cmd flow") from Sep 3, 2025 (linux-next), leads to the following
Smatch static checker warning:

	drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c:1459 edp_pr_get_state()
	warn: passing casted pointer 'state' to 'dc_wake_and_execute_gpint()' 64 vs 32.

drivers/gpu/drm/amd/amdgpu/../display/dc/link/protocols/link_edp_panel_control.c
    1448 bool edp_pr_get_state(const struct dc_link *link, uint64_t *state)
                                                           ^^^^^^^^^^^^^^^

    1449 {
    1450         const struct dc  *dc = link->ctx->dc;
    1451         unsigned int panel_inst = 0;
    1452         uint32_t retry_count = 0;
    1453 
    1454         if (!dc_get_edp_link_panel_inst(dc, link, &panel_inst))
    1455                 return false;
    1456 
    1457         do {
    1458                 // Send gpint command and wait for ack
--> 1459                 if (!dc_wake_and_execute_gpint(dc->ctx, DMUB_GPINT__GET_REPLAY_STATE, panel_inst,
    1460                                                (uint32_t *)state, DM_DMUB_WAIT_TYPE_WAIT_WITH_REPLY)) {
                                                        ^^^^^^^^^^^^^^^^^

The dc_wake_and_execute_gpint() function doesn't take a u64, it takes
a u32.  It tries to initialize the state to zero at the start but
that's not going to work because of the type mismatch.  It suggests
that callers are allowed to pass uninitialized data to
edp_pr_get_state() but at present there are no callers so this is
only a bug in the code but doesn't affect runtime.

    1461                         // Return invalid state when GPINT times out
    1462                         *state = PR_STATE_INVALID;
    1463                 }
    1464         } while (++retry_count <= 1000 && *state == PR_STATE_INVALID);
    1465 
    1466         // Assert if max retry hit
    1467         if (retry_count >= 1000 && *state == PR_STATE_INVALID) {
    1468                 ASSERT(0);
    1469                 /* To-do: Add retry fail log */
    1470         }
    1471 
    1472         return true;
    1473 }

regards,
dan carpenter