[Intel-gfx] [PATCH] drm/i915/audio: error log non-zero audio power refcount after unbind

[Kai Vehmanen]

Hi Jani,

On Fri, 17 Apr 2020, Jani Nikula wrote:

> We have some module unload/reload tests hitting an issue with i915
> unbinding the component interface before the audio driver has properly
> put the power. Log an error about it for ease of debugging. (Normally

thanks, this is a good addition:
Reviewed-by: Kai Vehmanen <kai.vehmanen at linux.intel.com>

Maybe one point to consider is whether to take the next step and just 
block the unload. On audio side, once acomp binding is done to i915 
driver, it is only released at hda driver unload. So any test case where 
audio driver is bound to i915, and test unloads i915 without unloading 
the audio driver first, will not work. Even if no immediate failure is 
seen at unload, functionality will be impacted after i915 is loaded 
again.

Not sure how to do this though. Normally module refcounts would take care
of this (and block i915 unload), but now that we have the component 
framework in between, something else is needed.

PS Audio driver also doesn't implement component unbind(), but I don't
   immediately see what it could do there. It can't return an error
   and the audio framework is not really prepared for invidual codec
   drivers to disappear at runtime. We can handle hotplug of complete 
   cards (like USB), but individual codec drivers are expected to stay loaded.