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| author | Anssi Hannula <anssi.hannula@iki.fi> | 2013-11-10 22:56:11 +0400 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2013-11-11 20:08:04 +0400 |
| commit | a5666824ce79f4e63e017c25f6e1d9b6e6f267b2 (patch) | |
| tree | e99df9cb2045eba760369eed35ed86098bd310d8 /sound/pci | |
| parent | 13122e6ebf24d9f676d8a40edc2e9a265e89b628 (diff) | |
| download | linux-a5666824ce79f4e63e017c25f6e1d9b6e6f267b2.tar.xz | |
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/pci')
| -rw-r--r-- | sound/pci/hda/hda_eld.c | 23 |
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 */ |