This is a note to let you know that I've just added the patch titled ALSA: hdsp: Break infinite MIDI input flush loop to the 6.6-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-hdsp-break-infinite-midi-input-flush-loop.patch and it can be found in the queue-6.6 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit e7fd9d012e95a4ae2e77fed0a0f6592e1c199217 Author: Takashi Iwai <tiwai@xxxxxxx> Date: Thu Aug 8 11:15:12 2024 +0200 ALSA: hdsp: Break infinite MIDI input flush loop [ Upstream commit c01f3815453e2d5f699ccd8c8c1f93a5b8669e59 ] 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@xxxxxxx Signed-off-by: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/sound/pci/rme9652/hdsp.c b/sound/pci/rme9652/hdsp.c index e7d1b43471a29..713ca262a0e97 100644 --- a/sound/pci/rme9652/hdsp.c +++ b/sound/pci/rme9652/hdsp.c @@ -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) diff --git a/sound/pci/rme9652/hdspm.c b/sound/pci/rme9652/hdspm.c index 267c7848974ae..74215f57f4fc9 100644 --- a/sound/pci/rme9652/hdspm.c +++ b/sound/pci/rme9652/hdspm.c @@ -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)