On Tue, 06 Oct 2020 14:13:40 +0200, Takashi Iwai wrote:
On Tue, 06 Oct 2020 13:30:40 +0200, Kai Vehmanen wrote:
Hi,
this simple bugfix started to feel a bit like getting stuck in quicksand, so I'm looking for some early input via this RFC series.
Basicly hdac_i915.c should not use global state to track communication with i915 driver. But how to get handle of "hdac_bus*? I considered a few options:
- add hdac_bus as a member of drm_audio_component.h
-> seems wrong as this is really an audio side implementation)
- embed copy of drm_audio_component to 'struct hdac_bus', so I could use container_of() on the device handle to get to the bus
-> wasted space to keep a copy at hdac_bus level (note: snd-hda-codec-hdmi do this by embedding a copy of ops to "struct hdmi_spec")
- add another devres entry to store the hdac_bus directly in acomp_init and a new helper function to query it
I now implemented option 3 in this RFC series as it seemed cleanest and most local to hdac_component.c, where the problem stems from. It's still somewhat messy, and I'm wondering if I'm overlooking some obvious alternative. We could dig this deeper into i915 specific code, but OTOH, hdac_bus is an argument snd_hdac_acomp_init(), so it's common for all.
Kai Vehmanen (2): ALSA: hda - keep track of HDA core bus instance in acomp ALSA: hda/i915 - fix list corruption with concurrent probes
Another option would be to move the completion into the common acomp helper from i915-specific one. That is,
Add bind_complete field into struct drm_audio_component, initialize it at snd_hdac_acomp_init()
Call complete_all(&acomp->bind_complete) at the end of hdac_component_master_bind()
Remove / replace i915's own completion with the hdac's one. The i915_init_ops can be dropped.
So something like below (totally untested).
Takashi
--- --- a/include/drm/drm_audio_component.h +++ b/include/drm/drm_audio_component.h @@ -117,6 +117,10 @@ struct drm_audio_component { * @audio_ops: Ops implemented by hda driver, called by DRM driver */ const struct drm_audio_component_audio_ops *audio_ops; + /** + * @master_bind_complete: completion held during component master binding + */ + struct completion master_bind_complete; };
#endif /* _DRM_AUDIO_COMPONENT_H_ */ --- a/sound/hda/hdac_component.c +++ b/sound/hda/hdac_component.c @@ -210,12 +210,14 @@ static int hdac_component_master_bind(struct device *dev) goto module_put; }
+ complete_all(&acomp->master_bind_complete); return 0;
module_put: module_put(acomp->ops->owner); out_unbind: component_unbind_all(dev, acomp); + complete_all(&acomp->master_bind_complete);
return ret; } @@ -296,6 +298,7 @@ int snd_hdac_acomp_init(struct hdac_bus *bus, if (!acomp) return -ENOMEM; acomp->audio_ops = aops; + init_completion(&acomp->master_bind_complete); bus->audio_component = acomp; devres_add(dev, acomp);
--- a/sound/hda/hdac_i915.c +++ b/sound/hda/hdac_i915.c @@ -11,8 +11,6 @@ #include <sound/hda_i915.h> #include <sound/hda_register.h>
-static struct completion bind_complete; - #define IS_HSW_CONTROLLER(pci) (((pci)->device == 0x0a0c) || \ ((pci)->device == 0x0c0c) || \ ((pci)->device == 0x0d0c) || \ @@ -130,19 +128,6 @@ static bool i915_gfx_present(void) return pci_dev_present(ids); }
-static int i915_master_bind(struct device *dev, - struct drm_audio_component *acomp) -{ - complete_all(&bind_complete); - /* clear audio_ops here as it was needed only for completion call */ - acomp->audio_ops = NULL; - return 0; -} - -static const struct drm_audio_component_audio_ops i915_init_ops = { - .master_bind = i915_master_bind -}; - /** * snd_hdac_i915_init - Initialize i915 audio component * @bus: HDA core bus @@ -163,9 +148,7 @@ int snd_hdac_i915_init(struct hdac_bus *bus) if (!i915_gfx_present()) return -ENODEV;
- init_completion(&bind_complete); - - err = snd_hdac_acomp_init(bus, &i915_init_ops, + err = snd_hdac_acomp_init(bus, NULL, i915_component_master_match, sizeof(struct i915_audio_component) - sizeof(*acomp)); if (err < 0) @@ -177,7 +160,7 @@ int snd_hdac_i915_init(struct hdac_bus *bus) if (!IS_ENABLED(CONFIG_MODULES) || !request_module("i915")) { /* 60s timeout */ - wait_for_completion_timeout(&bind_complete, + wait_for_completion_timeout(&acomp->master_bind_complete, msecs_to_jiffies(60 * 1000)); } }