On 07.12.2010 21:19, Anssi Hannula wrote:
> When a new HDMI/DP device is plugged in, hdmi_update_short_audio_desc()
> is called for every SAD (Short Audio Descriptor) in the ELD data. For
> LPCM coding type SAD defines the supported sample sizes. For several
> other coding types (such as AC-3), a maximum bitrate is defined.
>
> The maximum bitrate and sample size fields are not always cleared.
> Therefore, if a device is unplugged and a different one is plugged in,
> and the coding types of some SAD positions differ between the devices,
> the old max_bitrate or sample_bits values will persist if the new SADs
> do not define those values.
>
> The leftover max_bitrate and sample_bits do not cause any issues other
> than wrongly showing up in eld#X.Y procfs file and kernel log.
Actually, only max_bitrate will be shown there, the coding type seems to
be checked for LPCM before outputting sample_bits into eld#X.Y or log.
It is still probably better to clear that value as well, though.
> Fix that by always clearing sample_bits and max_bitrate when reading
> SADs.
>
> Signed-off-by: Anssi Hannula <anssi.hannula@xxxxxx>
> ---
> sound/pci/hda/hda_eld.c | 4 +++-
> 1 files changed, 3 insertions(+), 1 deletions(-)
>
> diff --git a/sound/pci/hda/hda_eld.c b/sound/pci/hda/hda_eld.c
> index 009031f..4a66347 100644
> --- a/sound/pci/hda/hda_eld.c
> +++ b/sound/pci/hda/hda_eld.c
> @@ -189,6 +189,9 @@ static void hdmi_update_short_audio_desc(struct cea_sad *a,
> a->channels = GRAB_BITS(buf, 0, 0, 3);
> a->channels++;
>
> + a->sample_bits = 0;
> + a->max_bitrate = 0;
> +
> a->format = GRAB_BITS(buf, 0, 3, 4);
> switch (a->format) {
> case AUDIO_CODING_TYPE_REF_STREAM_HEADER:
> @@ -198,7 +201,6 @@ static void hdmi_update_short_audio_desc(struct cea_sad *a,
>
> case AUDIO_CODING_TYPE_LPCM:
> val = GRAB_BITS(buf, 2, 0, 3);
> - a->sample_bits = 0;
> for (i = 0; i < 3; i++)
> if (val & (1 << i))
> a->sample_bits |= cea_sample_sizes[i + 1];
--
Anssi Hannula
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