}
EXPORT_SYMBOL(drm_dp_dpcd_read_link_status);
+/**
+ * drm_dp_send_real_edid_checksum() - send back real edid checksum value
+ * @aux: DisplayPort AUX channel
+ * @real_edid_checksum: real edid checksum for the last block
+ *
+ * Returns:
+ * True on success
+ */
+bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
+ u8 real_edid_checksum)
+{
+ u8 link_edid_read = 0, auto_test_req = 0, test_resp = 0;
+
+ if (drm_dp_dpcd_read(aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+ &auto_test_req, 1) < 1) {
+ DRM_ERROR("DPCD failed read at register 0x%x\n",
+ DP_DEVICE_SERVICE_IRQ_VECTOR);
+ return false;
+ }
+ auto_test_req &= DP_AUTOMATED_TEST_REQUEST;
+
+ if (drm_dp_dpcd_read(aux, DP_TEST_REQUEST, &link_edid_read, 1) < 1) {
+ DRM_ERROR("DPCD failed read at register 0x%x\n",
+ DP_TEST_REQUEST);
+ return false;
+ }
+ link_edid_read &= DP_TEST_LINK_EDID_READ;
+
+ if (!auto_test_req || !link_edid_read) {
+ DRM_DEBUG_KMS("Source DUT does not support TEST_EDID_READ\n");
+ return false;
+ }
+
+ if (drm_dp_dpcd_write(aux, DP_DEVICE_SERVICE_IRQ_VECTOR,
+ &auto_test_req, 1) < 1) {
+ DRM_ERROR("DPCD failed write at register 0x%x\n",
+ DP_DEVICE_SERVICE_IRQ_VECTOR);
+ return false;
+ }
+
+ /* send back checksum for the last edid extension block data */
+ if (drm_dp_dpcd_write(aux, DP_TEST_EDID_CHECKSUM,
+ &real_edid_checksum, 1) < 1) {
+ DRM_ERROR("DPCD failed write at register 0x%x\n",
+ DP_TEST_EDID_CHECKSUM);
+ return false;
+ }
+
+ test_resp |= DP_TEST_EDID_CHECKSUM_WRITE;
+ if (drm_dp_dpcd_write(aux, DP_TEST_RESPONSE, &test_resp, 1) < 1) {
+ DRM_ERROR("DPCD failed write at register 0x%x\n",
+ DP_TEST_RESPONSE);
+ return false;
+ }
+
+ return true;
+}
+EXPORT_SYMBOL(drm_dp_send_real_edid_checksum);
+
/**
* drm_dp_downstream_max_clock() - extract branch device max
* pixel rate for legacy VGA
static int drm_edid_block_checksum(const u8 *raw_edid)
{
int i;
- u8 csum = 0;
- for (i = 0; i < EDID_LENGTH; i++)
+ u8 csum = 0, crc = 0;
+
+ for (i = 0; i < EDID_LENGTH - 1; i++)
csum += raw_edid[i];
- return csum;
+ crc = 0x100 - csum;
+
+ return crc;
+}
+
+static bool drm_edid_block_checksum_diff(const u8 *raw_edid, u8 real_checksum)
+{
+ if (raw_edid[EDID_LENGTH - 1] != real_checksum)
+ return true;
+ else
+ return false;
}
static bool drm_edid_is_zero(const u8 *in_edid, int length)
}
csum = drm_edid_block_checksum(raw_edid);
- if (csum) {
+ if (drm_edid_block_checksum_diff(raw_edid, csum)) {
if (edid_corrupt)
*edid_corrupt = true;
u8 *edid, int num_blocks)
{
int i;
+ u8 num_of_ext = edid[0x7e];
+
+ /* Calculate real checksum for the last edid extension block data */
+ connector->real_edid_checksum =
+ drm_edid_block_checksum(edid + num_of_ext * EDID_LENGTH);
if (connector->bad_edid_counter++ && !drm_debug_enabled(DRM_UT_KMS))
return;
int drm_dp_dpcd_read_link_status(struct drm_dp_aux *aux,
u8 status[DP_LINK_STATUS_SIZE]);
+bool drm_dp_send_real_edid_checksum(struct drm_dp_aux *aux,
+ u8 real_edid_checksum);
+
int drm_dp_downstream_max_clock(const u8 dpcd[DP_RECEIVER_CAP_SIZE],
const u8 port_cap[4]);
int drm_dp_downstream_max_bpc(const u8 dpcd[DP_RECEIVER_CAP_SIZE],