drm/nv50/disp: force dac power state during load detect

fdo#64904
Reported-by: Gerhard Bräunlich <wippbox@gmx.net>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/core/engine/disp/dacnv50.c

@@ -50,11 +50,15 @@ nv50_dac_sense(struct nv50_disp_priv *priv, int or, u32 loadval)
 {
 	const u32 doff = (or * 0x800);
 	int load = -EINVAL;
+	nv_mask(priv, 0x61a004 + doff, 0x807f0000, 0x80150000);
+	nv_wait(priv, 0x61a004 + doff, 0x80000000, 0x00000000);
 	nv_wr32(priv, 0x61a00c + doff, 0x00100000 | loadval);
 	udelay(9500);
 	nv_wr32(priv, 0x61a00c + doff, 0x80000000);
 	load = (nv_rd32(priv, 0x61a00c + doff) & 0x38000000) >> 27;
 	nv_wr32(priv, 0x61a00c + doff, 0x00000000);
+	nv_mask(priv, 0x61a004 + doff, 0x807f0000, 0x80550000);
+	nv_wait(priv, 0x61a004 + doff, 0x80000000, 0x00000000);
 	return load;
 }
 

drivers/gpu/drm/nouveau/core/include/core/class.h

@@ -218,7 +218,7 @@ struct nv04_display_class {
 #define NV50_DISP_DAC_PWR_STATE                                      0x00000040
 #define NV50_DISP_DAC_PWR_STATE_ON                                   0x00000000
 #define NV50_DISP_DAC_PWR_STATE_OFF                                  0x00000040
-#define NV50_DISP_DAC_LOAD                                           0x0002000c
+#define NV50_DISP_DAC_LOAD                                           0x00020100
 #define NV50_DISP_DAC_LOAD_VALUE                                     0x00000007
 
 #define NV50_DISP_PIOR_MTHD                                          0x00030000