mISDN: Fixed false interruption of audio during bridging change.

Transmitted audio data was interrupted if a bridge was enabled or disabled.
Now transmission seamlessly continues during that action.
Fix in hfcmulti.ko
Signed-off-by: Andreas Eversberg <jolly@eversberg.eu>
Signed-off-by: Karsten Keil <keil@b1-systems.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/isdn/hardware/mISDN/hfcmulti.c

@@ -3018,8 +3018,10 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
 			HFC_outb(hc, A_CON_HDLC, 0x20 | V_HDLC_TRP | V_IFF);
 			HFC_outb(hc, A_SUBCH_CFG, 0);
 			HFC_outb(hc, A_IRQ_MSK, 0);
-			HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
-			HFC_wait(hc);
+			if (hc->chan[ch].protocol != protocol) {
+				HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
+				HFC_wait(hc);
+			}
 			HFC_outb(hc, R_SLOT, ((((ch / 4) * 8) +
 					       ((ch % 4) * 4) + 1) << 1) | 1);
 			HFC_outb(hc, A_SL_CFG, 0x80 | 0x20 | (ch << 1) | 1);
@@ -3039,8 +3041,10 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
 			HFC_outb(hc, A_CON_HDLC, 0x20 | V_HDLC_TRP | V_IFF);
 			HFC_outb(hc, A_SUBCH_CFG, 0);
 			HFC_outb(hc, A_IRQ_MSK, 0);
-			HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
-			HFC_wait(hc);
+			if (hc->chan[ch].protocol != protocol) {
+				HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
+				HFC_wait(hc);
+			}
 			/* tx silence */
 			HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, hc->silence);
 			HFC_outb(hc, R_SLOT, (((ch / 4) * 8) +
@@ -3059,8 +3063,10 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
 					 V_HDLC_TRP | V_IFF);
 			HFC_outb(hc, A_SUBCH_CFG, 0);
 			HFC_outb(hc, A_IRQ_MSK, 0);
-			HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
-			HFC_wait(hc);
+			if (hc->chan[ch].protocol != protocol) {
+				HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
+				HFC_wait(hc);
+			}
 			/* tx silence */
 			HFC_outb_nodebug(hc, A_FIFO_DATA0_NOINC, hc->silence);
 			/* enable RX fifo */
@@ -3075,8 +3081,10 @@ mode_hfcmulti(struct hfc_multi *hc, int ch, int protocol, int slot_tx,
 					 V_HDLC_TRP);
 			HFC_outb(hc, A_SUBCH_CFG, 0);
 			HFC_outb(hc, A_IRQ_MSK, 0);
-			HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
-			HFC_wait(hc);
+			if (hc->chan[ch].protocol != protocol) {
+				HFC_outb(hc, R_INC_RES_FIFO, V_RES_F);
+				HFC_wait(hc);
+			}
 		}
 		if (hc->ctype != HFC_TYPE_E1) {
 			hc->hw.a_st_ctrl0[hc->chan[ch].port] |=