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authorAnssi Hannula <anssi.hannula@iki.fi>2013-11-10 20:56:11 +0200
committerTakashi Iwai <tiwai@suse.de>2013-11-11 17:08:04 +0100
commita5666824ce79f4e63e017c25f6e1d9b6e6f267b2 (patch)
treee99df9cb2045eba760369eed35ed86098bd310d8 /sound
parent13122e6ebf24d9f676d8a40edc2e9a265e89b628 (diff)
ALSA: hda - hdmi: Skip out-of-range latency values in AMD ELD generator
The ATI/AMD video/audio latencies are specified in apparent HDMI VSDB format. In this format values above 251 are not valid (or stream component is not supported - 255), but no checking is performed since this was not mentioned in the AMD HDA verbs specification. Check that the latencies are valid before using them, and add a comment describing the formats. Signed-off-by: Anssi Hannula <anssi.hannula@iki.fi> Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound')
-rw-r--r--sound/pci/hda/hda_eld.c23
1 files changed, 19 insertions, 4 deletions
diff --git a/sound/pci/hda/hda_eld.c b/sound/pci/hda/hda_eld.c
index e8c55f5a34ff..9b697a28cf53 100644
--- a/sound/pci/hda/hda_eld.c
+++ b/sound/pci/hda/hda_eld.c
@@ -768,13 +768,28 @@ int snd_hdmi_get_eld_ati(struct hda_codec *codec, hda_nid_t nid,
return -EINVAL;
}
+ /*
+ * HDMI VSDB latency format:
+ * separately for both audio and video:
+ * 0 field not valid or unknown latency
+ * [1..251] msecs = (x-1)*2 (max 500ms with x = 251 = 0xfb)
+ * 255 audio/video not supported
+ *
+ * HDA latency format:
+ * single value indicating video latency relative to audio:
+ * 0 unknown or 0ms
+ * [1..250] msecs = x*2 (max 500ms with x = 250 = 0xfa)
+ * [251..255] reserved
+ */
aud_synch = snd_hda_codec_read(codec, nid, 0, ATI_VERB_GET_AUDIO_VIDEO_DELAY, 0);
if ((aud_synch & ATI_DELAY_VIDEO_LATENCY) && (aud_synch & ATI_DELAY_AUDIO_LATENCY)) {
- int video_latency = (aud_synch & ATI_DELAY_VIDEO_LATENCY) - 1;
- int audio_latency = ((aud_synch & ATI_DELAY_AUDIO_LATENCY) >> 8) - 1;
+ int video_latency_hdmi = (aud_synch & ATI_DELAY_VIDEO_LATENCY);
+ int audio_latency_hdmi = (aud_synch & ATI_DELAY_AUDIO_LATENCY) >> 8;
- if (video_latency > audio_latency)
- buf[6] = min(video_latency - audio_latency, 0xfa);
+ if (video_latency_hdmi <= 0xfb && audio_latency_hdmi <= 0xfb &&
+ video_latency_hdmi > audio_latency_hdmi)
+ buf[6] = video_latency_hdmi - audio_latency_hdmi;
+ /* else unknown/invalid or 0ms or video ahead of audio, so use zero */
}
/* Baseline length */