Re: [PATCH v2] ALSA: emu10k1: track loss of external clock on E-MU cards

[Takashi Iwai <tiwai@suse.de>]

On Sat, 15 Jul 2023 18:07:38 +0200,
Oswald Buddenhagen wrote:
> 
> This uses IRQs to track spontaneous changes to the word clock source
> register.
> 
> FWIW, that this can happen in the first place is the reason why it is
> futile to lock the clock source mixer setting while the device is open -
> we can't consistently control the rate anyway. Though arguably, we
> should reset any open streams when that happens, as they become
> corrupted anyway.
> 
> Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@gmx.de>
> 
> ---
> v2:
> - use driver-local lock instead of core's control_rwsem
> 
> ---
> FIXME? while i'm not sure, i think this won't notice seamless switches
> between 44.1 and 48 kHz. assuming that's the case, this seems like a
> minor issue: firstly, just about nothing actually produces such a
> seamless switch - my only device that can even do that is the e-mu card
> itself, but the driver disrupts that by temporarily muting the output.
> secondly, the user is unlikely to select an external source before
> setting it up properly. and the easy workaround is actually never doing
> that.
> regardless, to actually test that i'd need a second e-mu card.

The code change itself looks sane, so I took the patch as is now.


thanks,

Takashi