[PATCH] Fix potential NULL pointer dereference in echoaudio midi.

[Jesper Juhl <jesper.juhl@gmail.com>]

In sound/pci/echoaudio/midi.c::snd_echo_midi_output_write(), there's a risk
of dereferencing a NULL 'chip->midi_out'.
This patch contains the obvious fix as also used a bit higher up in the 
same function.


Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
---

diff --git a/sound/pci/echoaudio/midi.c b/sound/pci/echoaudio/midi.c
index e31f0f1..69ef9f0 100644
--- a/sound/pci/echoaudio/midi.c
+++ b/sound/pci/echoaudio/midi.c
@@ -236,7 +236,8 @@ static void snd_echo_midi_output_write(u
 	}
 
 	/* We restart the timer only if there is some data left to send */
-	if (!snd_rawmidi_transmit_empty(chip->midi_out) && chip->tinuse) {
+	if (chip->midi_out && !snd_rawmidi_transmit_empty(chip->midi_out) &&
+			chip->tinuse) {
 		/* The timer will expire slightly after the data has been
 		   sent */
 		time = (sent << 3) / 25 + 1;	/* 8/25=0.32ms to send a byte */