Date 13.5.2013 10:28, David Henningsson wrote:
On 05/13/2013 09:37 AM, Wang Xingchao wrote:
I915 module maybe loaded after snd_hda_intel, the power-well API doesnot exist in such case. This patch intended to avoid loading dependency between snd-hda-intel and i915 module.
Hi Xingchao and thanks for working on this.
This patch seems to re-do some of the work done in other patches (a lot of lines removed), so it's a little hard to follow. But I'll try to write some overall comments on how I have envisioned things...
- I don't think there's any need to create an additional kernel module,
we can just let hda_i915.c be in the snd-hda-intel.ko module, and only compile it if DRM_I915 is defined.
- We don't need an IS_HSW macro on the audio side. Instead declare a
new AZX_DCAPS_NEED_I915_POWER (or similar) driver quirk.
- Somewhere in the beginning of the probing in hda_intel.c, we'll need
something like:
if (driver_caps & AZX_DCAPS_NEED_I915_POWER) hda_i915_init(chip);
- The hda_i915_init does not need to be exported (they're now both in
the same module). hda_i915.h could have something like:
#ifdef DRM_I915 void hda_i915_init(chip); #else #define hda_i915_init(chip) do {} while(0) #endif
- You're saying this patch is about avoid loading dependency between
snd-hda-intel and i915 module. That does not make sense to me, since the powerwell API is in the i915 module, snd-hda-intel must load it when it wants to enable power on haswell, right? Thus there is a loading dependency. If the i915 module is not loaded at that point, we must wait for it to load, so we can have proper power, instead of continuing probing without the power well?
Looking to the code, if the drm code requires a callback to the audio code, I would just register it in the audio driver init phase and unregister it when snd-hda-intel is unloaded. This cross module loading dependency looks really bad. Or it is not allowed to load the audio driver later than DRM one?
Jaroslav