Currently i915_component_master_match() will return the first matching i915 instance. This does not work in case system has multiple i915 and HDA audio controller instances.
Add a new connectivity check that handles following cases: - i915 and HDA controller on same PCI bus - discrete GPU with embedded HDA audio controller connected via PCI bridge
Signed-off-by: Kai Vehmanen kai.vehmanen@linux.intel.com --- sound/hda/hdac_i915.c | 44 +++++++++++++++++++++++++++++++++++++++++-- 1 file changed, 42 insertions(+), 2 deletions(-)
diff --git a/sound/hda/hdac_i915.c b/sound/hda/hdac_i915.c index 3c2db3816029..50b2c1db429b 100644 --- a/sound/hda/hdac_i915.c +++ b/sound/hda/hdac_i915.c @@ -73,11 +73,51 @@ void snd_hdac_i915_set_bclk(struct hdac_bus *bus) } EXPORT_SYMBOL_GPL(snd_hdac_i915_set_bclk);
+/** + * Returns true if the devices can be connected for audio. + */ +static bool connectivity_check(struct pci_dev *i915, struct pci_dev *hdac) +{ + struct pci_bus *bus_a = i915->bus, *bus_b = hdac->bus; + + /* directly connected on the same bus */ + if (bus_a == bus_b) + return true; + + /* + * on i915 discrete GPUs with embedded HDA audio, the two + * devices are connected via 2nd level PCI bridge + */ + bus_a = bus_a->parent; + bus_b = bus_b->parent; + if (!bus_a || !bus_b) + return false; + bus_a = bus_a->parent; + bus_b = bus_b->parent; + if (bus_a && bus_a == bus_b) + return true; + + return false; +} + static int i915_component_master_match(struct device *dev, int subcomponent, void *data) { - return !strcmp(dev->driver->name, "i915") && - subcomponent == I915_COMPONENT_AUDIO; + struct pci_dev *hdac_pci, *i915_pci; + struct hdac_bus *bus = data; + + if (!dev_is_pci(dev)) + return 0; + + hdac_pci = to_pci_dev(bus->dev); + i915_pci = to_pci_dev(dev); + + if (!strcmp(dev->driver->name, "i915") && + subcomponent == I915_COMPONENT_AUDIO && + connectivity_check(i915_pci, hdac_pci)) + return 1; + + return 0; }
/* check whether intel graphics is present */