ALSA: hda/hdmi: Cancel pending works before suspend

The per_pin->work might be still floating at the suspend, and this may
hit the access to the hardware at an unexpected timing.  Cancel the
work properly at the suspend callback for avoiding the buggy access.

Note that the bug doesn't trigger easily in the recent kernels since
the work is queued only when the repoll count is set, and usually it's
only at the resume callback, but it's still possible to hit in
theory.

BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1182377Reported-and-tested-by: Abhishek Sahu <abhsahu@nvidia.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210310112809.9215-4-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_hdmi.c

@@ -2480,6 +2480,18 @@ static void generic_hdmi_free(struct hda_codec *codec)
 }
 
 #ifdef CONFIG_PM
+static int generic_hdmi_suspend(struct hda_codec *codec)
+{
+	struct hdmi_spec *spec = codec->spec;
+	int pin_idx;
+
+	for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) {
+		struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx);
+		cancel_delayed_work_sync(&per_pin->work);
+	}
+	return 0;
+}
+
 static int generic_hdmi_resume(struct hda_codec *codec)
 {
 	struct hdmi_spec *spec = codec->spec;
@@ -2503,6 +2515,7 @@ static const struct hda_codec_ops generic_hdmi_patch_ops = {
 	.build_controls		= generic_hdmi_build_controls,
 	.unsol_event		= hdmi_unsol_event,
 #ifdef CONFIG_PM
+	.suspend		= generic_hdmi_suspend,
 	.resume			= generic_hdmi_resume,
 #endif
 };