v4l2-dbg: report fail reason to the user

Commit Message

Németh Márton Nov. 12, 2009, 7:23 a.m. UTC

None

Patch

diff -r 60f784aa071d v4l2-apps/util/v4l2-dbg.cpp
--- a/v4l2-apps/util/v4l2-dbg.cpp	Wed Nov 11 18:28:53 2009 +0100
+++ b/v4l2-apps/util/v4l2-dbg.cpp	Thu Nov 12 08:21:20 2009 +0100
@@ -353,14 +353,21 @@ 
 static int doioctl(int fd, int request, void *parm, const char *name)
 {
 	int retVal;
+	int ioctl_errno;

 	if (!options[OptVerbose]) return ioctl(fd, request, parm);
 	retVal = ioctl(fd, request, parm);
-	printf("%s: ", name);
-	if (retVal < 0)
-		printf("failed: %s\n", strerror(errno));
-	else
-		printf("ok\n");
+	if (options[OptVerbose]) {
+		/* Save errno because printf() may modify it */
+		ioctl_errno = errno;
+		printf("%s: ", name);
+		if (retVal < 0)
+			printf("failed: %s\n", strerror(errno));
+		else
+			printf("ok\n");
+		/* Restore errno for caller's use */
+		errno = ioctl_errno;
+	}

 	return retVal;
 }
@@ -586,8 +593,8 @@ 

 				printf(" set to 0x%llx\n", set_reg.val);
 			} else {
-				printf("Failed to set register 0x%08llx value 0x%llx\n",
-					set_reg.reg, set_reg.val);
+				printf("Failed to set register 0x%08llx value 0x%llx: %s\n",
+					set_reg.reg, set_reg.val, strerror(errno));
 			}
 			set_reg.reg++;
 		}