Add hack to force the detection of a parallel cable by Stefan Ziegenbalg.

This hack is activated by preloading libusb-driver-trenz.so.

diff --git a/Makefile b/Makefile
index 4ef6abaddc493bf1a81fda7b43ae5c2a82368458..3325a89f5b026de9a160f90d68e72b97fbdd92c0 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -1,14 +1,19 @@
-CFLAGS=-Wall
+CFLAGS=-Wall -fPIC
 
-all: libusb-driver.so libusb-driver-DEBUG.so
+SOBJECTS=libusb-driver.so libusb-driver-DEBUG.so libusb-driver-trenz.so
+
+all: $(SOBJECTS)
 
 libusb-driver.so: usb-driver.c usb-driver.h
-       gcc -fPIC $(CFLAGS) $< -o $@ -ldl -lusb -lpthread -shared
+       gcc $(CFLAGS) $< -o $@ -ldl -lusb -lpthread -shared
+
+libusb-driver-trenz.so: usb-driver.c usb-driver.h
+       gcc -DTRENZ $(CFLAGS) $< -o $@ -ldl -lusb -lpthread -shared
 
 libusb-driver-DEBUG.so: usb-driver.c usb-driver.h
-       gcc -fPIC -DDEBUG $(CFLAGS) $< -o $@ -ldl -lusb -lpthread -shared
+       gcc -DDEBUG $(CFLAGS) $< -o $@ -ldl -lusb -lpthread -shared
 
 clean:
-       rm -f libusb-driver.so libusb-driver-DEBUG.so
+       rm -f $(SOBJECTS)
 
 .PHONY: clean all

diff --git a/README b/README
index 13737b53039f8a816b70561d28ea0a20ea8518fa..fcf211a6450369653ae4ee429d1f8538c18c096e 100644 (file)
--- a/README
+++ b/README
@@ -72,6 +72,11 @@ ppdev
 To use the device as an ordinary user, put the user in the group 'lp'
 
 
+If you have an almost compatible cable which works with other software but not
+with Impact, try preloading libusb-driver-trenz.so instead of libusb-driver.so.
+It includes a hack by Stefan Ziegenbalg to force detection of a parallel cable.
+
+
 Parallel Cable IV is currently only supported in 'compatibility mode', as no
 attempt to configure the ECP registers is done by this library.
 

diff --git a/usb-driver.c b/usb-driver.c
index fa2611e8c3ea19c9261a4f4488fa083554076aec..c497b506a86634edfa46f781c0a809ac0a63ae53 100644 (file)
--- a/usb-driver.c
+++ b/usb-driver.c
@@ -241,6 +241,7 @@ int pp_transfer(WD_TRANSFER *tr, int fd, unsigned int request, unsigned char *wd
        int ret = 0;
        unsigned long port = (unsigned long)tr->dwPort;
        unsigned char val;
+       static int last_pp_write = 0;
 
        DPRINTF("dwPort: 0x%lx, cmdTrans: %lu, dwbytes: %ld, fautoinc: %ld, dwoptions: %ld\n",
                        (unsigned long)tr->dwPort, tr->cmdTrans, tr->dwBytes,
@@ -268,6 +269,7 @@ int pp_transfer(WD_TRANSFER *tr, int fd, unsigned int request, unsigned char *wd
 
                        case PP_WRITE:
                                ret = ioctl(parportfd, PPWDATA, &val);
+                               last_pp_write = val;
                                break;
 
                        default:
@@ -276,10 +278,17 @@ int pp_transfer(WD_TRANSFER *tr, int fd, unsigned int request, unsigned char *wd
                                break;
                }
        } else if (port == ppbase + PP_STATUS) {
-               DPRINTF("status port\n");
+               DPRINTF("status port (last write: %d)\n", last_pp_write);
                switch(tr->cmdTrans) {
                        case PP_READ:
                                ret = ioctl(parportfd, PPRSTATUS, &val);
+#ifdef TRENZ
+                               val &= 95;
+                               if (last_pp_write & 64)
+                                       val |= 32;
+                               else
+                                       val |= 128;
+#endif
                                break;
 
                        case PP_WRITE: