ALSA: hdsp: Break infinite MIDI input flush loop

[ Upstream commit c01f381545 ]

The current MIDI input flush on HDSP and HDSPM drivers relies on the
hardware reporting the right value.  If the hardware doesn't give the
proper value but returns -1, it may be stuck at an infinite loop.

Add a counter and break if the loop is unexpectedly too long.

Link: https://patch.msgid.link/20240808091513.31380-1-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Takashi Iwai 2024-08-08 11:15:12 +02:00 committed by Greg Kroah-Hartman
parent 7a55740996
commit 6cc4e5eaad
2 changed files with 8 additions and 4 deletions

View File

@ -1298,8 +1298,10 @@ static int snd_hdsp_midi_output_possible (struct hdsp *hdsp, int id)
static void snd_hdsp_flush_midi_input (struct hdsp *hdsp, int id)
{
while (snd_hdsp_midi_input_available (hdsp, id))
snd_hdsp_midi_read_byte (hdsp, id);
int count = 256;
while (snd_hdsp_midi_input_available(hdsp, id) && --count)
snd_hdsp_midi_read_byte(hdsp, id);
}
static int snd_hdsp_midi_output_write (struct hdsp_midi *hmidi)

View File

@ -1838,8 +1838,10 @@ static inline int snd_hdspm_midi_output_possible (struct hdspm *hdspm, int id)
static void snd_hdspm_flush_midi_input(struct hdspm *hdspm, int id)
{
while (snd_hdspm_midi_input_available (hdspm, id))
snd_hdspm_midi_read_byte (hdspm, id);
int count = 256;
while (snd_hdspm_midi_input_available(hdspm, id) && --count)
snd_hdspm_midi_read_byte(hdspm, id);
}
static int snd_hdspm_midi_output_write (struct hdspm_midi *hmidi)