[Nut-upsdev] Driver fix for Ippon BCP800 (06da/0003), blazer_usb.c

[Danya Alexeyevsky]

Hi,

Thanks to some older discussions on this list I found it quite easy to
eventually track down problem with using USB cable with some more of
Megatec/Q1 UPSes. The trick (which is done in megatec_usb, but not in
blazer_usb) is to read in the junk that somehow gets into read buffers
before sending any commands. (I inserted debug statements so it's easy
to see that the data read is really junk: in my case it's most often a
middle piece of previous query and sometimes is appended with some
fragments of /proc/self/environment or something).

I will appreciate if you apply the patch to fix it (although probably
it's better to have some such flush function defined in usb wrappers
for every needing driver to use):

Index: drivers/blazer_usb.c
===================================================================
--- drivers/blazer_usb.c	(revision 1896)
+++ drivers/blazer_usb.c	(working copy)
@@ -94,6 +94,23 @@
 }


+static int phoenix_flush_io()
+{
+	static
+	char buf[SMALLBUF+1];
+	int i, ret;
+	upsdebugx(3, "phoenix_flush_io");
+	for(i = 0; i < 10; i++) {
+		memset(buf, 0, sizeof(buf));
+		/* ret = usb->get_interrupt(udev, (unsigned char *)buf, 8, 1000); */
+		ret = usb_interrupt_read(udev, 0x81, buf, SMALLBUF, 1000);
+		upsdebugx(4, "flush(%d,%d) <- '%s'", ret, strlen(buf), buf);
+		if (ret < 1)
+			break;
+	}
+	return 0;
+}
+
 static int phoenix_command(const char *cmd, char *buf, size_t buflen)
 {
 	char	tmp[SMALLBUF];
@@ -103,6 +120,7 @@
 	memset(tmp, 0, sizeof(tmp));
 	snprintf(tmp, sizeof(tmp), "%s", cmd);

+	phoenix_flush_io();
 	for (i = 0; i < strlen(tmp); i += ret) {

 		/* Write data in 8-byte chunks */

After this patch the driver seems to work OK.

Cheers,
-- Danya