drm/amd/display: Block dynamic IPS2 on DCN35 for incompatible FW versions

[WHY]
Hangs with Z8 can occur if running an older unfixed PMFW version.

[HOW]
Fallback to RCG only for dynamic IPS2 states if it's not newer than
93.12. Limit to DCN35.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Reviewed-by: Charlene Liu <charlene.liu@amd.com>
Signed-off-by: Nicholas Kazlauskas <nicholas.kazlauskas@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Tested-by: Daniel Wheeler <daniel.wheeler@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/clk_mgr/dcn35/dcn35_clk_mgr.c

@@ -1222,6 +1222,12 @@ void dcn35_clk_mgr_construct(
 			ctx->dc->debug.disable_dpp_power_gate = false;
 			ctx->dc->debug.disable_hubp_power_gate = false;
 			ctx->dc->debug.disable_dsc_power_gate = false;
+
+			/* Disable dynamic IPS2 in older PMFW (93.12) for Z8 interop. */
+			if (ctx->dc->config.disable_ips == DMUB_IPS_ENABLE &&
+			    ctx->dce_version == DCN_VERSION_3_5 &&
+			    ((clk_mgr->base.smu_ver & 0x00FFFFFF) <= 0x005d0c00))
+				ctx->dc->config.disable_ips = DMUB_IPS_RCG_IN_ACTIVE_IPS2_IN_OFF;
 		} else {
 			/*let's reset the config control flag*/
 			ctx->dc->config.disable_ips = DMUB_IPS_DISABLE_ALL; /*pmfw not support it, disable it all*/