[alsa-devel] [PATCH] ALSA: hda - Reset sample sizes and max bitrates when reading ELD

Takashi Iwai tiwai at suse.de
Wed Dec 8 08:37:49 CET 2010

At Tue, 07 Dec 2010 22:21:57 +0200,
Anssi Hannula wrote:
> 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.

Fair enough.  I took your patch as is now.



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