Re: [PATCH 1/5] HDA : patch_sigmatel.c : cleanups

[Maxim Levitsky <maximlevitsky@gmail.com>]

On Saturday 01 September 2007 14:49:29 Takashi Iwai wrote:
> At Sat, 1 Sep 2007 11:11:24 +0300,
> Maxim Levitsky wrote:
> > 
> > On Friday 31 August 2007 13:56:19 Takashi Iwai wrote:
> > > At Tue, 28 Aug 2007 12:46:01 +0200,
> > > I wrote:
> > > > 
> > > > At Tue, 28 Aug 2007 05:07:48 +0300,
> > > > Maxim Levitsky wrote:
> > > > > 
> > > > > From c9392b0293f7d39e40e4a5e07e7b140d5a385079 Mon Sep 17 00:00:00 2001
> > > > > From: Maxim Levitsky <maximlevitsky@gmail.com>
> > > > > Date: Mon, 27 Aug 2007 22:49:49 +0300
> > > > > Subject: [PATCH] HDA : patch_sigmatel.c : cleanups
> > > > 
> > > > OK, it's a nice clean-up.  Can be merged as is.
> > > 
> > > Now merged to ALSA HG tree.
> > > 
> > > If the fixes for other patches are ready, please let me know.
> > > I'll merge them to HG tree, too.
> > > 
> > > 
> > > Thanks,
> > > 
> > > Takashi
> > > 
> > 
> > 
> > Hi,
> > 
> > I run into unexpected problems:
> > latest hg adds a power saving mode to hda codec, and while the idea is nice, it plays very bad with my patches.
> > 
> > 1) The analog loop-back becomes a nightmare, since power-saving code turns the codec off, but for loopback to function it has to be powered.
> > I tried to add a snd_hda_power_up/down calls to .put function, and while it did stop the unwanted powerdown of codec, on resume from ram , analog loopback vanishes.
> > any access to device (arecord/aplay or any mixer change make analog loop work again).
> > Can you tell me how I properly tell the core that user _uses_ the device, and device should be powered.
> > 
> > 2) on resume all playback apps hang, and recording (arecord) exits with message "Resource temporary unavailable"
> > restarting apps help.
> 
> First, you need to use snd_hda_codec_write_cache() for values to be
> resumed, especially in control put callbacks.  The amp values accessed
> via snd_hda_codec_amp_update() are always cached, but
> snd_hda_codec_write() doesn't cache.
> 
> The second thing is analog-loopback.  The driver should keep the power
> when the analog-loopback is on, and enables power-saving again when
> it's off.  So far, I thought only the amp controls, but now it's a
> different one.
> 
> In this case, the put callback would need to call snd_hda_pwoer_up()
> and snd_hda_power_down() appropriately to turn on/off power-save.
> They should be called only at transition.  Namely, when 0->1
> transition of spec->aloopback occurs in put callback, it calls
> snd_hda_power_up().  When 1->0 occurs, call snd_hda_power_down().
> 
> 
> Takashi
> 

Hi,
	Well, did you read my email?  :-)

	I did call snd_hda_power_up/down in .put callback, but as I said, on resume, driver didn't powered up the codec, and as usual any access to device
	powers up the codec.

	Well and I found another bug,
	The problem is that on resume all "use mic/line-in as output' controls are disabled, and I know why:

	.resume() before introduction of snd_hda_codec_write_cache() / dynamic power managment:
		stac92xx_init() -> inits inputs/outputs of chip (sets all dynamic pins to output mode)

		snd_hda_resume_ctls() > hacky, but working way of resuming mixer controls : read from memory, write to device
		

	.resume() now:
		stac92xx_init() -> inits inputs/outputs of chip (sets all dynamic pins to output mode), and touches the command cache.
		snd_hda_codec_resume_cache() writes (modifed) cache to codec, thus making dynamic outputs be in input mode.

	I suggest skipping call to stac92xx_init()  at all, after all no initialization is nessesary, since all commands are in cache.

Best regards,
	Maxim Levitsky