Add example command for mounting debugfs

This is a nice opportunity to teach the user something, (and help our
users to actually succeed in creating useful bug reports for us).

diff --git a/tools/intel_gpu_dump.c b/tools/intel_gpu_dump.c
index 23af24f..8ddfbd3 100644 (file)
--- a/tools/intel_gpu_dump.c
+++ b/tools/intel_gpu_dump.c
@@ -1953,7 +1953,10 @@ main (int argc, char *argv[])
            path = "/sys/kernel/debug/dri/0";
            err = stat(path, &st);
            if (err != 0) {
-               errx(1, "Couldn't find i915 debugfs directory\n");
+               errx(1,
+                    "Couldn't find i915 debugfs directory.\n\n"
+                    "Is debugfs mounted? You might try mounting it with a command such as:\n\n"
+                    "\tsudo mount -t debugfs debugfs /sys/kernel/debug\n");
            }
        }
     } else {