drm/amd/display: disable FPO and SubVP for older DMUB versions on DCN32x

There have recently been changes that break backwards compatibility,
that were introduced into DMUB firmware (for DCN32x) concerning FPO and
SubVP. So, since those are just power optimization features, we can just
disable them unless the user is using a new enough version of DMUB
firmware.

Cc: stable@vger.kernel.org
Link: https://gitlab.freedesktop.org/drm/amd/-/issues/2870
Fixes: ed6e2782 ("drm/amd/display: For cursor P-State allow for SubVP")
Reported-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Closes: https://lore.kernel.org/r/CABXGCsNRb0QbF2pKLJMDhVOKxyGD6-E+8p-4QO6FOWa6zp22_A@mail.gmail.com/Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Signed-off-by: Hamza Mahfooz <hamza.mahfooz@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/hwss/dcn32/dcn32_hwseq.c

@@ -960,6 +960,12 @@ void dcn32_init_hw(struct dc *dc)
 		dc->caps.dmub_caps.subvp_psr = dc->ctx->dmub_srv->dmub->feature_caps.subvp_psr_support;
 		dc->caps.dmub_caps.gecc_enable = dc->ctx->dmub_srv->dmub->feature_caps.gecc_enable;
 		dc->caps.dmub_caps.mclk_sw = dc->ctx->dmub_srv->dmub->feature_caps.fw_assisted_mclk_switch;
+
+		if (dc->ctx->dmub_srv->dmub->fw_version <
+		    DMUB_FW_VERSION(7, 0, 35)) {
+			dc->debug.force_disable_subvp = true;
+			dc->debug.disable_fpo_optimizations = true;
+		}
 	}
 }