[bug report] drm/amd/display: Disable MALL SS and messages for PSR supported configs

[bug report] drm/amd/display: Disable MALL SS and messages for PSR supported configs

[Dan Carpenter]

Hello Dillon Varone,

This is a semi-automatic email about new static checker warnings.

The patch 0bed85e48af1: "drm/amd/display: Disable MALL SS and
messages for PSR supported configs" from Jan 4, 2023, leads to the
following Smatch complaint:

    drivers/gpu/drm/amd/amdgpu/../display/dc/dcn32/dcn32_hwseq.c:257 dcn32_apply_idle_power_optimizations()
    warn: variable dereferenced before check 'dc->current_state' (see line 249)

drivers/gpu/drm/amd/amdgpu/../display/dc/dcn32/dcn32_hwseq.c
   248	
   249		for (i = 0; i < dc->current_state->stream_count; i++) {
                                ^^^^^^^^^^^^^^^^^^^
Patch adds unchecked dereference

   250			/* MALL SS messaging is not supported with PSR at this time */
   251			if (dc->current_state->streams[i] != NULL &&
   252					dc->current_state->streams[i]->link->psr_settings.psr_version != DC_PSR_VERSION_UNSUPPORTED)
   253				return false;
   254		}
   255	
   256		if (enable) {
   257			if (dc->current_state) {
                        ^^^^^^^^^^^^^^^^^^^^^^^^
Checked too late.

   258	
   259				/* 1. Check no memory request case for CAB.

regards,
dan carpenter