drm/nouveau/disp/dp: support aux read interval during link training

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/disp/dport.c

@@ -48,7 +48,7 @@ struct dp_state {
 	u8 version;
 	struct nouveau_i2c_port *aux;
 	int head;
-	u8  dpcd[4];
+	u8  dpcd[16];
 	int link_nr;
 	u32 link_bw;
 	u8  stat[6];
@@ -149,7 +149,10 @@ dp_link_train_update(struct dp_state *dp, u32 delay)
 {
 	int ret;
 
-	udelay(delay);
+	if (dp->dpcd[DPCD_RC0E_AUX_RD_INTERVAL])
+		mdelay(dp->dpcd[DPCD_RC0E_AUX_RD_INTERVAL] * 4);
+	else
+		udelay(delay);
 
 	ret = nv_rdaux(dp->aux, DPCD_LS02, dp->stat, 6);
 	if (ret)

drivers/gpu/drm/nouveau/core/engine/disp/dport.h

@@ -2,15 +2,14 @@
 #define __NVKM_DISP_DPORT_H__
 
 /* DPCD Receiver Capabilities */
-#define DPCD_RC00                                                       0x00000
-#define DPCD_RC00_DPCD_REV                                                 0xff
-#define DPCD_RC01                                                       0x00001
-#define DPCD_RC01_MAX_LINK_RATE                                            0xff
+#define DPCD_RC00_DPCD_REV                                              0x00000
+#define DPCD_RC01_MAX_LINK_RATE                                         0x00001
 #define DPCD_RC02                                                       0x00002
 #define DPCD_RC02_ENHANCED_FRAME_CAP                                       0x80
 #define DPCD_RC02_MAX_LANE_COUNT                                           0x1f
 #define DPCD_RC03                                                       0x00003
 #define DPCD_RC03_MAX_DOWNSPREAD                                           0x01
+#define DPCD_RC0E_AUX_RD_INTERVAL                                       0x0000e
 
 /* DPCD Link Configuration */
 #define DPCD_LC00                                                       0x00100