drm/radeon/kms: detect sideport memory on IGP chips

This detects if the sideport memory is enabled and
if it is VRAM is evicted on suspend/resume.

This should fix s/r issues on some IGPs.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/radeon_atombios.c b/drivers/gpu/drm/radeon/radeon_atombios.c
index 1834035..fa82ca7 100644
--- a/drivers/gpu/drm/radeon/radeon_atombios.c
+++ b/drivers/gpu/drm/radeon/radeon_atombios.c
@@ -938,6 +938,43 @@
 	return false;
 }
 
+union igp_info {
+	struct _ATOM_INTEGRATED_SYSTEM_INFO info;
+	struct _ATOM_INTEGRATED_SYSTEM_INFO_V2 info_2;
+};
+
+bool radeon_atombios_sideport_present(struct radeon_device *rdev)
+{
+	struct radeon_mode_info *mode_info = &rdev->mode_info;
+	int index = GetIndexIntoMasterTable(DATA, IntegratedSystemInfo);
+	union igp_info *igp_info;
+	u8 frev, crev;
+	u16 data_offset;
+
+	atom_parse_data_header(mode_info->atom_context, index, NULL, &frev,
+			       &crev, &data_offset);
+
+	igp_info = (union igp_info *)(mode_info->atom_context->bios +
+				      data_offset);
+
+	if (igp_info) {
+		switch (crev) {
+		case 1:
+			if (igp_info->info.ucMemoryType & 0xf0)
+				return true;
+			break;
+		case 2:
+			if (igp_info->info_2.ucMemoryType & 0x0f)
+				return true;
+			break;
+		default:
+			DRM_ERROR("Unsupported IGP table: %d %d\n", frev, crev);
+			break;
+		}
+	}
+	return false;
+}
+
 bool radeon_atombios_get_tmds_info(struct radeon_encoder *encoder,
 				   struct radeon_encoder_int_tmds *tmds)
 {