8 files changed, 228 insertions, 159 deletions

diff --git a/drivers/isdn/hardware/mISDN/avmfritz.c b/drivers/isdn/hardware/mISDN/avmfritz.c
index 7cd3a963ed2e..c6fa505a1d1b 100644
--- a/drivers/isdn/hardware/mISDN/avmfritz.c
+++ b/drivers/isdn/hardware/mISDN/avmfritz.c
@@ -30,7 +30,7 @@
 #include "ipac.h"
 
 
-#define AVMFRITZ_REV    "2.2"
+#define AVMFRITZ_REV    "2.3"
 
 static int AVM_cnt;
 static int debug;
@@ -442,19 +442,26 @@ hdlc_fill_fifo(struct bchannel *bch)
 {
         struct fritzcard *fc = bch->hw;
         struct hdlc_hw *hdlc;
-        int count, fs, cnt = 0;
+        int count, fs, cnt = 0, idx, fillempty = 0;
         u8 *p;
         u32 *ptr, val, addr;
 
-        hdlc = &fc->hdlc[(bch->nr - 1) & 1];
-        if (!bch->tx_skb)
-                return;
-        count = bch->tx_skb->len - bch->tx_idx;
-        if (count <= 0)
-                return;
+        idx = (bch->nr - 1) & 1;
+        hdlc = &fc->hdlc[idx];
         fs = (fc->type == AVM_FRITZ_PCIV2) ?
                 HDLC_FIFO_SIZE_V2 : HDLC_FIFO_SIZE_V1;
-        p = bch->tx_skb->data + bch->tx_idx;
+        if (!bch->tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &bch->Flags))
+                        return;
+                count = fs;
+                p = bch->fill;
+                fillempty = 1;
+        } else {
+                count = bch->tx_skb->len - bch->tx_idx;
+                if (count <= 0)
+                        return;
+                p = bch->tx_skb->data + bch->tx_idx;
+        }
         hdlc->ctrl.sr.cmd &= ~HDLC_CMD_XME;
         if (count > fs) {
                 count = fs;
@@ -462,10 +469,14 @@ hdlc_fill_fifo(struct bchannel *bch)
                 if (test_bit(FLG_HDLC, &bch->Flags))
                         hdlc->ctrl.sr.cmd |= HDLC_CMD_XME;
         }
-        pr_debug("%s: %s %d/%d/%d", fc->name, __func__, count,
-                 bch->tx_idx, bch->tx_skb->len);
         ptr = (u32 *)p;
-        bch->tx_idx += count;
+        if (fillempty) {
+                pr_debug("%s.B%d: %d/%d/%d", fc->name, bch->nr, count,
+                         bch->tx_idx, bch->tx_skb->len);
+                bch->tx_idx += count;
+        } else {
+                pr_debug("%s.B%d: fillempty %d\n", fc->name, bch->nr, count);
+        }
         hdlc->ctrl.sr.xml = ((count == fs) ? 0 : count);
         if (fc->type == AVM_FRITZ_PCIV2) {
                 __write_ctrl_pciv2(fc, hdlc, bch->nr);
@@ -475,13 +486,21 @@ hdlc_fill_fifo(struct bchannel *bch)
                 __write_ctrl_pci(fc, hdlc, bch->nr);
                 addr = fc->addr + CHIP_WINDOW;
         }
-        while (cnt < count) {
-                val = get_unaligned(ptr);
-                outl(cpu_to_le32(val), addr);
-                ptr++;
-                cnt += 4;
+        if (fillempty) {
+                while (cnt < count) {
+                        /* all bytes the same - no worry about endian */
+                        outl(*ptr, addr);
+                        cnt += 4;
+                }
+        } else {
+                while (cnt < count) {
+                        val = get_unaligned(ptr);
+                        outl(cpu_to_le32(val), addr);
+                        ptr++;
+                        cnt += 4;
+                }
         }
-        if (debug & DEBUG_HW_BFIFO) {
+        if ((debug & DEBUG_HW_BFIFO) && !fillempty) {
                 snprintf(fc->log, LOG_SIZE, "B%1d-send %s %d ",
                          bch->nr, fc->name, count);
                 print_hex_dump_bytes(fc->log, DUMP_PREFIX_OFFSET, p, count);
@@ -496,8 +515,12 @@ HDLC_irq_xpr(struct bchannel *bch)
         } else {
                 if (bch->tx_skb)
                         dev_kfree_skb(bch->tx_skb);
-                if (get_next_bframe(bch))
+                if (get_next_bframe(bch)) {
                         hdlc_fill_fifo(bch);
+                        test_and_clear_bit(FLG_TX_EMPTY, &bch->Flags);
+                } else if (test_bit(FLG_TX_EMPTY, &bch->Flags)) {
+                        hdlc_fill_fifo(bch);
+                }
         }
 }
 
@@ -561,6 +584,8 @@ handle_tx:
                 if (bch->tx_skb && bch->tx_skb->len) {
                         if (!test_bit(FLG_TRANSPARENT, &bch->Flags))
                                 bch->tx_idx = 0;
+                } else if (test_bit(FLG_FILLEMPTY, &bch->Flags)) {
+                        test_and_set_bit(FLG_TX_EMPTY, &bch->Flags);
                 }
                 hdlc->ctrl.sr.xml = 0;
                 hdlc->ctrl.sr.cmd |= HDLC_CMD_XRS;
@@ -882,7 +907,6 @@ open_bchannel(struct fritzcard *fc, struct channel_req *rq)
         bch = &fc->bch[rq->adr.channel - 1];
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch;
         return 0;
diff --git a/drivers/isdn/hardware/mISDN/hfcmulti.c b/drivers/isdn/hardware/mISDN/hfcmulti.c
index 3d4b36d2a31a..db9b04519829 100644
--- a/drivers/isdn/hardware/mISDN/hfcmulti.c
+++ b/drivers/isdn/hardware/mISDN/hfcmulti.c
@@ -3576,7 +3576,7 @@ channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
         case MISDN_CTRL_GETOP:
                 ret = mISDN_ctrl_bchannel(bch, cq);
                 cq->op |= MISDN_CTRL_HFC_OP | MISDN_CTRL_HW_FEATURES_OP |
-                          MISDN_CTRL_RX_OFF | MISDN_CTRL_FILL_EMPTY;
+                          MISDN_CTRL_RX_OFF;
                 break;
         case MISDN_CTRL_RX_OFF: /* turn off / on rx stream */
                 hc->chan[bch->slot].rx_off = !!cq->p1;
@@ -3591,11 +3591,10 @@ channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
                         printk(KERN_DEBUG "%s: RX_OFF request (nr=%d off=%d)\n",
                                __func__, bch->nr, hc->chan[bch->slot].rx_off);
                 break;
-        case MISDN_CTRL_FILL_EMPTY: /* fill fifo, if empty */
-                test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
-                if (debug & DEBUG_HFCMULTI_MSG)
-                        printk(KERN_DEBUG "%s: FILL_EMPTY request (nr=%d "
-                               "off=%d)\n", __func__, bch->nr, !!cq->p1);
+        case MISDN_CTRL_FILL_EMPTY:
+                ret = mISDN_ctrl_bchannel(bch, cq);
+                hc->silence = bch->fill[0];
+                memset(hc->silence_data, hc->silence, sizeof(hc->silence_data));
                 break;
         case MISDN_CTRL_HW_FEATURES: /* fill features structure */
                 if (debug & DEBUG_HFCMULTI_MSG)
@@ -4118,7 +4117,6 @@ open_bchannel(struct hfc_multi *hc, struct dchannel *dch,
         }
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         hc->chan[ch].rx_off = 0;
         rq->ch = &bch->ch;
diff --git a/drivers/isdn/hardware/mISDN/hfcpci.c b/drivers/isdn/hardware/mISDN/hfcpci.c
index 27743754ab81..1bd8bc7eb5c7 100644
--- a/drivers/isdn/hardware/mISDN/hfcpci.c
+++ b/drivers/isdn/hardware/mISDN/hfcpci.c
@@ -565,11 +565,6 @@ hfcpci_empty_fifo_trans(struct bchannel *bch, struct bzfifo *rxbz,
         if (new_z2 >= (B_FIFO_SIZE + B_SUB_VAL))
                 new_z2 -= B_FIFO_SIZE;  /* buffer wrap */
 
-        if (fcnt_rx > MAX_DATA_SIZE) {  /* flush, if oversized */
-                *z2r = cpu_to_le16(new_z2);             /* new position */
-                return;
-        }
-
         fcnt_tx = le16_to_cpu(*z2t) - le16_to_cpu(*z1t);
         if (fcnt_tx <= 0)
                 fcnt_tx += B_FIFO_SIZE;
@@ -761,9 +756,14 @@ hfcpci_fill_fifo(struct bchannel *bch)
 
         if ((bch->debug & DEBUG_HW_BCHANNEL) && !(bch->debug & DEBUG_HW_BFIFO))
                 printk(KERN_DEBUG "%s\n", __func__);
-        if ((!bch->tx_skb) || bch->tx_skb->len <= 0)
-                return;
-        count = bch->tx_skb->len - bch->tx_idx;
+        if ((!bch->tx_skb) || bch->tx_skb->len == 0) {
+                if (!test_bit(FLG_FILLEMPTY, &bch->Flags) &&
+                    !test_bit(FLG_TRANSPARENT, &bch->Flags))
+                        return;
+                count = HFCPCI_FILLEMPTY;
+        } else {
+                count = bch->tx_skb->len - bch->tx_idx;
+        }
         if ((bch->nr & 2) && (!hc->hw.bswapped)) {
                 bz = &((union fifo_area *)(hc->hw.fifos))->b_chans.txbz_b2;
                 bdata = ((union fifo_area *)(hc->hw.fifos))->b_chans.txdat_b2;
@@ -782,16 +782,10 @@ hfcpci_fill_fifo(struct bchannel *bch)
                 fcnt = le16_to_cpu(*z2t) - le16_to_cpu(*z1t);
                 if (fcnt <= 0)
                         fcnt += B_FIFO_SIZE;
-                /* fcnt contains available bytes in fifo */
-                fcnt = B_FIFO_SIZE - fcnt;
-                /* remaining bytes to send (bytes in fifo) */
-
-                /* "fill fifo if empty" feature */
-                if (test_bit(FLG_FILLEMPTY, &bch->Flags) && !fcnt) {
-                        /* printk(KERN_DEBUG "%s: buffer empty, so we have "
-                           "underrun\n", __func__); */
-                        /* fill buffer, to prevent future underrun */
-                        count = HFCPCI_FILLEMPTY;
+                if (test_bit(FLG_FILLEMPTY, &bch->Flags)) {
+                        /* fcnt contains available bytes in fifo */
+                        if (count > fcnt)
+                                count = fcnt;
                         new_z1 = le16_to_cpu(*z1t) + count;
                         /* new buffer Position */
                         if (new_z1 >= (B_FIFO_SIZE + B_SUB_VAL))
@@ -803,17 +797,20 @@ hfcpci_fill_fifo(struct bchannel *bch)
                                 printk(KERN_DEBUG "hfcpci_FFt fillempty "
                                        "fcnt(%d) maxl(%d) nz1(%x) dst(%p)\n",
                                        fcnt, maxlen, new_z1, dst);
-                        fcnt += count;
                         if (maxlen > count)
                                 maxlen = count;         /* limit size */
-                        memset(dst, 0x2a, maxlen);      /* first copy */
+                        memset(dst, bch->fill[0], maxlen); /* first copy */
                         count -= maxlen;                /* remaining bytes */
                         if (count) {
                                 dst = bdata;            /* start of buffer */
-                                memset(dst, 0x2a, count);
+                                memset(dst, bch->fill[0], count);
                         }
                         *z1t = cpu_to_le16(new_z1);     /* now send data */
+                        return;
                 }
+                /* fcnt contains available bytes in fifo */
+                fcnt = B_FIFO_SIZE - fcnt;
+                /* remaining bytes to send (bytes in fifo) */
 
         next_t_frame:
                 count = bch->tx_skb->len - bch->tx_idx;
@@ -1531,24 +1528,7 @@ deactivate_bchannel(struct bchannel *bch)
 static int
 channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 {
-        int     ret = 0;
-
-        switch (cq->op) {
-        case MISDN_CTRL_GETOP:
-                ret = mISDN_ctrl_bchannel(bch, cq);
-                cq->op |= MISDN_CTRL_FILL_EMPTY;
-                break;
-        case MISDN_CTRL_FILL_EMPTY: /* fill fifo, if empty */
-                test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
-                if (debug & DEBUG_HW_OPEN)
-                        printk(KERN_DEBUG "%s: FILL_EMPTY request (nr=%d "
-                               "off=%d)\n", __func__, bch->nr, !!cq->p1);
-                break;
-        default:
-                ret = mISDN_ctrl_bchannel(bch, cq);
-                break;
-        }
-        return ret;
+        return mISDN_ctrl_bchannel(bch, cq);
 }
 static int
 hfc_bctrl(struct mISDNchannel *ch, u_int cmd, void *arg)
@@ -1964,7 +1944,6 @@ open_bchannel(struct hfc_pci *hc, struct channel_req *rq)
         bch = &hc->bch[rq->adr.channel - 1];
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch; /* TODO: E-channel */
         if (!try_module_get(THIS_MODULE))
diff --git a/drivers/isdn/hardware/mISDN/hfcsusb.c b/drivers/isdn/hardware/mISDN/hfcsusb.c
index 9c17473da83b..b539b10d6f3e 100644
--- a/drivers/isdn/hardware/mISDN/hfcsusb.c
+++ b/drivers/isdn/hardware/mISDN/hfcsusb.c
@@ -491,7 +491,6 @@ open_bchannel(struct hfcsusb *hw, struct channel_req *rq)
         bch = &hw->bch[rq->adr.channel - 1];
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch;
 
@@ -806,24 +805,7 @@ hfcsusb_ph_command(struct hfcsusb *hw, u_char command)
 static int
 channel_bctrl(struct bchannel *bch, struct mISDN_ctrl_req *cq)
 {
-        int     ret = 0;
-
-        switch (cq->op) {
-        case MISDN_CTRL_GETOP:
-                ret = mISDN_ctrl_bchannel(bch, cq);
-                cq->op |= MISDN_CTRL_FILL_EMPTY;
-                break;
-        case MISDN_CTRL_FILL_EMPTY: /* fill fifo, if empty */
-                test_and_set_bit(FLG_FILLEMPTY, &bch->Flags);
-                if (debug & DEBUG_HW_OPEN)
-                        printk(KERN_DEBUG "%s: FILL_EMPTY request (nr=%d "
-                               "off=%d)\n", __func__, bch->nr, !!cq->p1);
-                break;
-        default:
-                ret = mISDN_ctrl_bchannel(bch, cq);
-                break;
-        }
-        return ret;
+        return mISDN_ctrl_bchannel(bch, cq);
 }
 
 /* collect data from incoming interrupt or isochron USB data */
@@ -1183,8 +1165,8 @@ tx_iso_complete(struct urb *urb)
         int k, tx_offset, num_isoc_packets, sink, remain, current_len,
                 errcode, hdlc, i;
         int *tx_idx;
-        int frame_complete, fifon, status;
-        __u8 threshbit;
+        int frame_complete, fifon, status, fillempty = 0;
+        __u8 threshbit, *p;
 
         spin_lock(&hw->lock);
         if (fifo->stop_gracefull) {
@@ -1202,6 +1184,9 @@ tx_iso_complete(struct urb *urb)
                 tx_skb = fifo->bch->tx_skb;
                 tx_idx = &fifo->bch->tx_idx;
                 hdlc = test_bit(FLG_HDLC, &fifo->bch->Flags);
+                if (!tx_skb && !hdlc &&
+                    test_bit(FLG_FILLEMPTY, &fifo->bch->Flags))
+                        fillempty = 1;
         } else {
                 printk(KERN_DEBUG "%s: %s: neither BCH nor DCH\n",
                        hw->name, __func__);
@@ -1260,6 +1245,8 @@ tx_iso_complete(struct urb *urb)
                         /* Generate next ISO Packets */
                         if (tx_skb)
                                 remain = tx_skb->len - *tx_idx;
+                        else if (fillempty)
+                                remain = 15; /* > not complete */
                         else
                                 remain = 0;
 
@@ -1290,15 +1277,20 @@ tx_iso_complete(struct urb *urb)
                                 }
 
                                 /* copy tx data to iso-urb buffer */
-                                memcpy(context_iso_urb->buffer + tx_offset + 1,
-                                       (tx_skb->data + *tx_idx), current_len);
-                                *tx_idx += current_len;
-
+                                p = context_iso_urb->buffer + tx_offset + 1;
+                                if (fillempty) {
+                                        memset(p, fifo->bch->fill[0],
+                                               current_len);
+                                } else {
+                                        memcpy(p, (tx_skb->data + *tx_idx),
+                                               current_len);
+                                        *tx_idx += current_len;
+                                }
                                 urb->iso_frame_desc[k].offset = tx_offset;
                                 urb->iso_frame_desc[k].length = current_len + 1;
 
                                 /* USB data log for every D ISO out */
-                                if ((fifon == HFCUSB_D_RX) &&
+                                if ((fifon == HFCUSB_D_RX) && !fillempty &&
                                     (debug & DBG_HFC_USB_VERBOSE)) {
                                         printk(KERN_DEBUG
                                                "%s: %s (%d/%d) offs(%d) len(%d) ",
diff --git a/drivers/isdn/hardware/mISDN/mISDNipac.c b/drivers/isdn/hardware/mISDN/mISDNipac.c
index 3e71a5ef4bbc..374a17751ffb 100644
--- a/drivers/isdn/hardware/mISDN/mISDNipac.c
+++ b/drivers/isdn/hardware/mISDN/mISDNipac.c
@@ -969,22 +969,28 @@ hscx_fill_fifo(struct hscx_hw *hscx)
         int count, more;
         u8 *p;
 
-        if (!hscx->bch.tx_skb)
-                return;
-        count = hscx->bch.tx_skb->len - hscx->bch.tx_idx;
-        if (count <= 0)
-                return;
-        p = hscx->bch.tx_skb->data + hscx->bch.tx_idx;
-
-        more = test_bit(FLG_TRANSPARENT, &hscx->bch.Flags) ? 1 : 0;
-        if (count > hscx->fifo_size) {
+        if (!hscx->bch.tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &hscx->bch.Flags))
+                        return;
                 count = hscx->fifo_size;
                 more = 1;
-        }
-        pr_debug("%s: B%1d %d/%d/%d\n", hscx->ip->name, hscx->bch.nr, count,
-                 hscx->bch.tx_idx, hscx->bch.tx_skb->len);
-        hscx->bch.tx_idx += count;
+                p = hscx->log;
+                memset(p, hscx->bch.fill[0], count);
+        } else {
+                count = hscx->bch.tx_skb->len - hscx->bch.tx_idx;
+                if (count <= 0)
+                        return;
+                p = hscx->bch.tx_skb->data + hscx->bch.tx_idx;
 
+                more = test_bit(FLG_TRANSPARENT, &hscx->bch.Flags) ? 1 : 0;
+                if (count > hscx->fifo_size) {
+                        count = hscx->fifo_size;
+                        more = 1;
+                }
+                pr_debug("%s: B%1d %d/%d/%d\n", hscx->ip->name, hscx->bch.nr,
+                         count, hscx->bch.tx_idx, hscx->bch.tx_skb->len);
+                hscx->bch.tx_idx += count;
+        }
         if (hscx->ip->type & IPAC_TYPE_IPACX)
                 hscx->ip->write_fifo(hscx->ip->hw,
                                      hscx->off + IPACX_XFIFOB, p, count);
@@ -995,7 +1001,7 @@ hscx_fill_fifo(struct hscx_hw *hscx)
         }
         hscx_cmdr(hscx, more ? 0x08 : 0x0a);
 
-        if (hscx->bch.debug & DEBUG_HW_BFIFO) {
+        if (hscx->bch.tx_skb && (hscx->bch.debug & DEBUG_HW_BFIFO)) {
                 snprintf(hscx->log, 64, "B%1d-send %s %d ",
                          hscx->bch.nr, hscx->ip->name, count);
                 print_hex_dump_bytes(hscx->log, DUMP_PREFIX_OFFSET, p, count);
@@ -1010,8 +1016,12 @@ hscx_xpr(struct hscx_hw *hx)
         } else {
                 if (hx->bch.tx_skb)
                         dev_kfree_skb(hx->bch.tx_skb);
-                if (get_next_bframe(&hx->bch))
+                if (get_next_bframe(&hx->bch)) {
                         hscx_fill_fifo(hx);
+                        test_and_clear_bit(FLG_TX_EMPTY, &hx->bch.Flags);
+                } else if (test_bit(FLG_TX_EMPTY, &hx->bch.Flags)) {
+                        hscx_fill_fifo(hx);
+                }
         }
 }
 
@@ -1128,7 +1138,9 @@ ipac_irq(struct hscx_hw *hx, u8 ista)
 
         if (istab & IPACX_B_XDU) {
                 if (test_bit(FLG_TRANSPARENT, &hx->bch.Flags)) {
-                        hscx_fill_fifo(hx);
+                        if (test_bit(FLG_FILLEMPTY, &hx->bch.Flags))
+                                test_and_set_bit(FLG_TX_EMPTY, &hx->bch.Flags);
+                        hscx_xpr(hx);
                         return;
                 }
                 pr_debug("%s: B%1d XDU error at len %d\n", hx->ip->name,
diff --git a/drivers/isdn/hardware/mISDN/mISDNisar.c b/drivers/isdn/hardware/mISDN/mISDNisar.c
index e74ad385e73f..901be3257a7b 100644
--- a/drivers/isdn/hardware/mISDN/mISDNisar.c
+++ b/drivers/isdn/hardware/mISDN/mISDNisar.c
@@ -585,16 +585,25 @@ isar_fill_fifo(struct isar_ch *ch)
         u8 msb;
         u8 *ptr;
 
-        pr_debug("%s: ch%d  tx_skb %p tx_idx %d\n",
-                 ch->is->name, ch->bch.nr, ch->bch.tx_skb, ch->bch.tx_idx);
-        if (!ch->bch.tx_skb)
+        pr_debug("%s: ch%d  tx_skb %d tx_idx %d\n", ch->is->name, ch->bch.nr,
+                 ch->bch.tx_skb ? ch->bch.tx_skb->len : -1, ch->bch.tx_idx);
+        if (!(ch->is->bstat &
+              (ch->dpath == 1 ? BSTAT_RDM1 : BSTAT_RDM2)))
+                return;
+        if (!ch->bch.tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &ch->bch.Flags) ||
+                    (ch->bch.state != ISDN_P_B_RAW))
+                        return;
+                count = ch->mml;
+                /* use the card buffer */
+                memset(ch->is->buf, ch->bch.fill[0], count);
+                send_mbox(ch->is, SET_DPS(ch->dpath) | ISAR_HIS_SDATA,
+                          0, count, ch->is->buf);
                 return;
+        }
         count = ch->bch.tx_skb->len - ch->bch.tx_idx;
         if (count <= 0)
                 return;
-        if (!(ch->is->bstat &
-              (ch->dpath == 1 ? BSTAT_RDM1 : BSTAT_RDM2)))
-                return;
         if (count > ch->mml) {
                 msb = 0;
                 count = ch->mml;
@@ -673,9 +682,9 @@ sel_bch_isar(struct isar_hw *isar, u8 dpath)
 static void
 send_next(struct isar_ch *ch)
 {
-        pr_debug("%s: %s ch%d tx_skb %p tx_idx %d\n",
-                 ch->is->name, __func__, ch->bch.nr,
-                 ch->bch.tx_skb, ch->bch.tx_idx);
+        pr_debug("%s: %s ch%d tx_skb %d tx_idx %d\n", ch->is->name, __func__,
+                 ch->bch.nr, ch->bch.tx_skb ? ch->bch.tx_skb->len : -1,
+                 ch->bch.tx_idx);
         if (ch->bch.state == ISDN_P_B_T30_FAX) {
                 if (ch->cmd == PCTRL_CMD_FTH) {
                         if (test_bit(FLG_LASTDATA, &ch->bch.Flags)) {
@@ -693,6 +702,9 @@ send_next(struct isar_ch *ch)
                 dev_kfree_skb(ch->bch.tx_skb);
         if (get_next_bframe(&ch->bch)) {
                 isar_fill_fifo(ch);
+                test_and_clear_bit(FLG_TX_EMPTY, &ch->bch.Flags);
+        } else if (test_bit(FLG_TX_EMPTY, &ch->bch.Flags)) {
+                isar_fill_fifo(ch);
         } else {
                 if (test_and_clear_bit(FLG_DLEETX, &ch->bch.Flags)) {
                         if (test_and_clear_bit(FLG_LASTDATA,
@@ -707,6 +719,8 @@ send_next(struct isar_ch *ch)
                         } else {
                                 deliver_status(ch, HW_MOD_CONNECT);
                         }
+                } else if (test_bit(FLG_FILLEMPTY, &ch->bch.Flags)) {
+                        test_and_set_bit(FLG_TX_EMPTY, &ch->bch.Flags);
                 }
         }
 }
@@ -1638,7 +1652,6 @@ isar_open(struct isar_hw *isar, struct channel_req *rq)
         bch = &isar->ch[rq->adr.channel - 1].bch;
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch;
         return 0;
diff --git a/drivers/isdn/hardware/mISDN/netjet.c b/drivers/isdn/hardware/mISDN/netjet.c
index 47d30749d8a7..aa95cc7d32f9 100644
--- a/drivers/isdn/hardware/mISDN/netjet.c
+++ b/drivers/isdn/hardware/mISDN/netjet.c
@@ -533,22 +533,31 @@ static void
 fill_dma(struct tiger_ch *bc)
 {
         struct tiger_hw *card = bc->bch.hw;
-        int count, i;
-        u32 m, v;
+        int count, i, fillempty = 0;
+        u32 m, v, n = 0;
         u8  *p;
 
         if (bc->free == 0)
                 return;
-        count = bc->bch.tx_skb->len - bc->bch.tx_idx;
-        if (count <= 0)
-                return;
-        pr_debug("%s: %s B%1d %d/%d/%d/%d state %x idx %d/%d\n", card->name,
-                 __func__, bc->bch.nr, count, bc->free, bc->bch.tx_idx,
-                 bc->bch.tx_skb->len, bc->txstate, bc->idx, card->send.idx);
+        if (!bc->bch.tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &bc->bch.Flags))
+                        return;
+                fillempty = 1;
+                count = card->send.size >> 1;
+                p = bc->bch.fill;
+        } else {
+                count = bc->bch.tx_skb->len - bc->bch.tx_idx;
+                if (count <= 0)
+                        return;
+                pr_debug("%s: %s B%1d %d/%d/%d/%d state %x idx %d/%d\n",
+                         card->name, __func__, bc->bch.nr, count, bc->free,
+                         bc->bch.tx_idx, bc->bch.tx_skb->len, bc->txstate,
+                         bc->idx, card->send.idx);
+                p = bc->bch.tx_skb->data + bc->bch.tx_idx;
+        }
         if (bc->txstate & (TX_IDLE | TX_INIT | TX_UNDERRUN))
                 resync(bc, card);
-        p = bc->bch.tx_skb->data + bc->bch.tx_idx;
-        if (test_bit(FLG_HDLC, &bc->bch.Flags)) {
+        if (test_bit(FLG_HDLC, &bc->bch.Flags) && !fillempty) {
                 count = isdnhdlc_encode(&bc->hsend, p, count, &i,
                                         bc->hsbuf, bc->free);
                 pr_debug("%s: B%1d hdlc encoded %d in %d\n", card->name,
@@ -559,17 +568,33 @@ fill_dma(struct tiger_ch *bc)
         } else {
                 if (count > bc->free)
                         count = bc->free;
-                bc->bch.tx_idx += count;
+                if (!fillempty)
+                        bc->bch.tx_idx += count;
                 bc->free -= count;
         }
         m = (bc->bch.nr & 1) ? 0xffffff00 : 0xffff00ff;
-        for (i = 0; i < count; i++) {
-                if (bc->idx >= card->send.size)
-                        bc->idx = 0;
-                v = card->send.start[bc->idx];
-                v &= m;
-                v |= (bc->bch.nr & 1) ? (u32)(p[i]) : ((u32)(p[i])) << 8;
-                card->send.start[bc->idx++] = v;
+        if (fillempty) {
+                n = p[0];
+                if (!(bc->bch.nr & 1))
+                        n <<= 8;
+                for (i = 0; i < count; i++) {
+                        if (bc->idx >= card->send.size)
+                                bc->idx = 0;
+                        v = card->send.start[bc->idx];
+                        v &= m;
+                        v |= n;
+                        card->send.start[bc->idx++] = v;
+                }
+        } else {
+                for (i = 0; i < count; i++) {
+                        if (bc->idx >= card->send.size)
+                                bc->idx = 0;
+                        v = card->send.start[bc->idx];
+                        v &= m;
+                        n = p[i];
+                        v |= (bc->bch.nr & 1) ? n : n << 8;
+                        card->send.start[bc->idx++] = v;
+                }
         }
         if (debug & DEBUG_HW_BFIFO) {
                 snprintf(card->log, LOG_SIZE, "B%1d-send %s %d ",
@@ -584,17 +609,26 @@ fill_dma(struct tiger_ch *bc)
 static int
 bc_next_frame(struct tiger_ch *bc)
 {
+        int ret = 1;
+
         if (bc->bch.tx_skb && bc->bch.tx_idx < bc->bch.tx_skb->len) {
                 fill_dma(bc);
         } else {
                 if (bc->bch.tx_skb)
                         dev_kfree_skb(bc->bch.tx_skb);
-                if (get_next_bframe(&bc->bch))
+                if (get_next_bframe(&bc->bch)) {
                         fill_dma(bc);
-                else
-                        return 0;
+                        test_and_clear_bit(FLG_TX_EMPTY, &bc->bch.Flags);
+                } else if (test_bit(FLG_TX_EMPTY, &bc->bch.Flags)) {
+                        fill_dma(bc);
+                } else if (test_bit(FLG_FILLEMPTY, &bc->bch.Flags)) {
+                        test_and_set_bit(FLG_TX_EMPTY, &bc->bch.Flags);
+                        ret = 0;
+                } else {
+                        ret = 0;
+                }
         }
-        return 1;
+        return ret;
 }
 
 static void
diff --git a/drivers/isdn/hardware/mISDN/w6692.c b/drivers/isdn/hardware/mISDN/w6692.c
index 03fb4a34fd53..183181f01927 100644
--- a/drivers/isdn/hardware/mISDN/w6692.c
+++ b/drivers/isdn/hardware/mISDN/w6692.c
@@ -498,16 +498,22 @@ static void
 W6692_fill_Bfifo(struct w6692_ch *wch)
 {
         struct w6692_hw *card = wch->bch.hw;
-        int count;
+        int count, fillempty = 0;
         u8 *ptr, cmd = W_B_CMDR_RACT | W_B_CMDR_XMS;
 
         pr_debug("%s: fill Bfifo\n", card->name);
-        if (!wch->bch.tx_skb)
-                return;
-        count = wch->bch.tx_skb->len - wch->bch.tx_idx;
-        if (count <= 0)
-                return;
-        ptr = wch->bch.tx_skb->data + wch->bch.tx_idx;
+        if (!wch->bch.tx_skb) {
+                if (!test_bit(FLG_TX_EMPTY, &wch->bch.Flags))
+                        return;
+                ptr = wch->bch.fill;
+                count = W_B_FIFO_THRESH;
+                fillempty = 1;
+        } else {
+                count = wch->bch.tx_skb->len - wch->bch.tx_idx;
+                if (count <= 0)
+                        return;
+                ptr = wch->bch.tx_skb->data + wch->bch.tx_idx;
+        }
         if (count > W_B_FIFO_THRESH)
                 count = W_B_FIFO_THRESH;
         else if (test_bit(FLG_HDLC, &wch->bch.Flags))
@@ -516,9 +522,16 @@ W6692_fill_Bfifo(struct w6692_ch *wch)
         pr_debug("%s: fill Bfifo%d/%d\n", card->name,
                  count, wch->bch.tx_idx);
         wch->bch.tx_idx += count;
-        outsb(wch->addr + W_B_XFIFO, ptr, count);
+        if (fillempty) {
+                while (count > 0) {
+                        outsb(wch->addr + W_B_XFIFO, ptr, MISDN_BCH_FILL_SIZE);
+                        count -= MISDN_BCH_FILL_SIZE;
+                }
+        } else {
+                outsb(wch->addr + W_B_XFIFO, ptr, count);
+        }
         WriteW6692B(wch, W_B_CMDR, cmd);
-        if (debug & DEBUG_HW_DFIFO) {
+        if ((debug & DEBUG_HW_BFIFO) && !fillempty) {
                 snprintf(card->log, 63, "B%1d-send %s %d ",
                          wch->bch.nr, card->name, count);
                 print_hex_dump_bytes(card->log, DUMP_PREFIX_OFFSET, ptr, count);
@@ -637,8 +650,12 @@ send_next(struct w6692_ch *wch)
         } else {
                 if (wch->bch.tx_skb)
                         dev_kfree_skb(wch->bch.tx_skb);
-                if (get_next_bframe(&wch->bch))
+                if (get_next_bframe(&wch->bch)) {
+                        W6692_fill_Bfifo(wch);
+                        test_and_clear_bit(FLG_TX_EMPTY, &wch->bch.Flags);
+                } else if (test_bit(FLG_TX_EMPTY, &wch->bch.Flags)) {
                         W6692_fill_Bfifo(wch);
+                }
         }
 }
 
@@ -727,8 +744,8 @@ W6692B_interrupt(struct w6692_hw *card, int ch)
                                  wch->bch.nr, star);
                 }
                 if (star & W_B_STAR_XDOW) {
-                        pr_debug("%s: B%d XDOW proto=%x\n", card->name,
-                                 wch->bch.nr, wch->bch.state);
+                        pr_warning("%s: B%d XDOW proto=%x\n", card->name,
+                                   wch->bch.nr, wch->bch.state);
 #ifdef ERROR_STATISTIC
                         wch->bch.err_xdu++;
 #endif
@@ -741,20 +758,21 @@ W6692B_interrupt(struct w6692_hw *card, int ch)
                         }
                 }
                 send_next(wch);
-                if (stat & W_B_EXI_XDUN)
+                if (star & W_B_STAR_XDOW)
                         return; /* handle XDOW only once */
         }
         if (stat & W_B_EXI_XDUN) {
-                pr_debug("%s: B%d XDUN proto=%x\n", card->name,
-                         wch->bch.nr, wch->bch.state);
+                pr_warning("%s: B%d XDUN proto=%x\n", card->name,
+                           wch->bch.nr, wch->bch.state);
 #ifdef ERROR_STATISTIC
                 wch->bch.err_xdu++;
 #endif
-                WriteW6692B(wch, W_B_CMDR, W_B_CMDR_XRST | W_B_CMDR_RACT);
-                /* resend */
+                /* resend - no XRST needed */
                 if (wch->bch.tx_skb) {
                         if (!test_bit(FLG_TRANSPARENT, &wch->bch.Flags))
                                 wch->bch.tx_idx = 0;
+                } else if (test_bit(FLG_FILLEMPTY, &wch->bch.Flags)) {
+                        test_and_set_bit(FLG_TX_EMPTY, &wch->bch.Flags);
                 }
                 send_next(wch);
         }
@@ -993,7 +1011,6 @@ open_bchannel(struct w6692_hw *card, struct channel_req *rq)
         bch = &card->bc[rq->adr.channel - 1].bch;
         if (test_and_set_bit(FLG_OPEN, &bch->Flags))
                 return -EBUSY; /* b-channel can be only open once */
-        test_and_clear_bit(FLG_FILLEMPTY, &bch->Flags);
         bch->ch.protocol = rq->protocol;
         rq->ch = &bch->ch;
         return 0;