ALSA: hda/intel: stop probe if DMICS are detected on Skylake+ platforms

The legacy HD-Audio driver cannot handle Skylake+ platforms with
digital microphones. For those platforms, the SOF or SST drivers need
to be used.

This patch provides an automatic way of detecting the presence of
DMICs using NHTL information reported by the BIOS. A kernel kconfig
option or a kernel module parameter provide an opt-in means of
stopping the probe. The kernel would then look for an alternate driver
registered for the same PCI ID to probe.

With this capability, distros no longer have to blacklist
snd-hda-intel, but still need to make sure the SOF/SST drivers are
functional by providing the relevant firmware and topology files in
/lib/firmware/intel

The coexistence between SOF and SST drivers and their dynamic
detection is not addressed by this patch, different mechanisms need to
be used, e.g. DMI-based quirks.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 34 insertions, 0 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index cb8b0945547c..ae9c13248a1d 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -46,6 +46,7 @@
 #include <sound/initval.h>
 #include <sound/hdaudio.h>
 #include <sound/hda_i915.h>
+#include <sound/intel-nhlt.h>
 #include <linux/vgaarb.h>
 #include <linux/vga_switcheroo.h>
 #include <linux/firmware.h>
@@ -124,6 +125,7 @@ static char *patch[SNDRV_CARDS];
 static bool beep_mode[SNDRV_CARDS] = {[0 ... (SNDRV_CARDS-1)] =
 					CONFIG_SND_HDA_INPUT_BEEP_MODE};
 #endif
+static bool dmic_detect = IS_ENABLED(CONFIG_SND_HDA_INTEL_DETECT_DMIC);
 
 module_param_array(index, int, NULL, 0444);
 MODULE_PARM_DESC(index, "Index value for Intel HD audio interface.");
@@ -158,6 +160,8 @@ module_param_array(beep_mode, bool, NULL, 0444);
 MODULE_PARM_DESC(beep_mode, "Select HDA Beep registration mode "
 			    "(0=off, 1=on) (default=1).");
 #endif
+module_param(dmic_detect, bool, 0444);
+MODULE_PARM_DESC(dmic_detect, "DMIC detect on SKL+ platforms");
 
 #ifdef CONFIG_PM
 static int param_set_xint(const char *val, const struct kernel_param *kp);
@@ -2025,6 +2029,25 @@ static const struct hda_controller_ops pci_hda_ops = {
 	.position_check = azx_position_check,
 };
 
+static int azx_check_dmic(struct pci_dev *pci, struct azx *chip)
+{
+	struct nhlt_acpi_table *nhlt;
+	int ret = 0;
+
+	if (chip->driver_type == AZX_DRIVER_SKL &&
+	    pci->class != 0x040300) {
+		nhlt = intel_nhlt_init(&pci->dev);
+		if (nhlt) {
+			if (intel_nhlt_get_dmic_geo(&pci->dev, nhlt)) {
+				ret = -ENODEV;
+				dev_info(&pci->dev, "Digital mics found on Skylake+ platform, aborting probe\n");
+			}
+			intel_nhlt_free(nhlt);
+		}
+	}
+	return ret;
+}
+
 static int azx_probe(struct pci_dev *pci,
 		     const struct pci_device_id *pci_id)
 {
@@ -2055,6 +2078,17 @@ static int azx_probe(struct pci_dev *pci,
 	card->private_data = chip;
 	hda = container_of(chip, struct hda_intel, chip);
 
+	/*
+	 * stop probe if digital microphones detected on Skylake+ platform
+	 * with the DSP enabled. This is an opt-in behavior defined at build
+	 * time or at run-time with a module parameter
+	 */
+	if (dmic_detect) {
+		err = azx_check_dmic(pci, chip);
+		if (err < 0)
+			goto out_free;
+	}
+
 	pci_set_drvdata(pci, card);
 
 	err = register_vga_switcheroo(chip);