From mboxrd@z Thu Jan  1 00:00:00 1970
From: Takashi Iwai <tiwai@suse.de>
Subject: Re: [PATCH] ALSA: usb-audio: Recurse before saving
	terminal properties
Date: Fri, 14 Aug 2015 15:06:58 +0200
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References: <1439410499-28630-1-git-send-email-julian@jusst.de>
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To: Julian Scheel <julian@jusst.de>
Cc: alsa-devel@alsa-project.org, Daniel Mack <daniel@zonque.org>
List-Id: alsa-devel@alsa-project.org

On Wed, 12 Aug 2015 22:14:59 +0200,
Julian Scheel wrote:
> 
> When the descriptor parser recurses into the clock source descriptor, the
> terminals properties, like name and type, are set to the values of the clock
> selector as check_input_term overwrites term->name and others in the recursive
> call. As we want to only fill missing values using the descriptors higher in
> the recursion tree the properties taken from the actual descriptor must be
> applied after recursing.
> 
> Signed-off-by: Julian Scheel <julian@jusst.de>

Thanks for the patch.  I vaguely remember of a similar patch, maybe
you who already sent.  One thing I find uncertain is whether this
breaks the current logic completely, namely:

> @@ -715,15 +715,16 @@ static int check_input_term(struct mixer_build *state, int id,
>  				term->name = d->iTerminal;
>  			} else { /* UAC_VERSION_2 */
>  				struct uac2_input_terminal_descriptor *d = p1;
> -				term->type = le16_to_cpu(d->wTerminalType);
> -				term->channels = d->bNrChannels;
> -				term->chconfig = le32_to_cpu(d->bmChannelConfig);
> -				term->name = d->iTerminal;
>  
>  				/* call recursively to get the clock selectors */
>  				err = check_input_term(state, d->bCSourceID, term);
>  				if (err < 0)
>  					return err;
> +
> +				term->type = le16_to_cpu(d->wTerminalType);
> +				term->channels = d->bNrChannels;
> +				term->chconfig = le32_to_cpu(d->bmChannelConfig);
> +				term->name = d->iTerminal;

... by this override, essentially all fields except for id are
restored.  Then what's the point to call check_input_term() for the
clock source?

Maybe Daniel can answer better how the original code is supposed to
work.  Daniel?


Takashi