ALSA: HD-Audio: SKL+: force HDaudio legacy or SKL+ driver selection

For HDaudio and Skylake drivers, add module parameter "pci_binding"

When pci_binding == 0 (AUTO), the PCI class/subclass info is used to
select drivers based on the presence of the DSP.

pci_binding == 1 (LEGACY) forces the use of the HDAudio legacy driver,
even if the DSP is present.

pci_binding == 2 (ASOC) forces the use of the ASOC driver. The
information on the DSP presence is bypassed.

The value for the module parameter needs to be identical for both
drivers. This parameter is intended as a back-up solution if the
automatic detection fails or when the DSP usage fails. Such cases
should be reported on the alsa-devel mailing list for analysis.

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

1 files changed, 23 insertions, 3 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 2ec9c896ebc0..e42cc2230977 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -172,6 +172,9 @@ 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
+static int skl_pci_binding;
+module_param_named(pci_binding, skl_pci_binding, int, 0444);
+MODULE_PARM_DESC(pci_binding, "PCI binding (0=auto, 1=only legacy, 2=only asoc");
 
 #ifdef CONFIG_PM
 static int param_set_xint(const char *val, const struct kernel_param *kp);
@@ -2050,9 +2053,26 @@ static int azx_probe(struct pci_dev *pci,
 	int err;
 
 	/* check if this driver can be used on SKL+ Intel platforms */
-	if ((pci_id->driver_data & AZX_DCAPS_INTEL_SHARED) &&
-	    pci->class != 0x040300)
-		return -ENODEV;
+	if (pci_id->driver_data & AZX_DCAPS_INTEL_SHARED) {
+		switch (skl_pci_binding) {
+		case SND_SKL_PCI_BIND_AUTO:
+			if (pci->class != 0x040300) {
+				dev_info(&pci->dev, "The DSP is enabled on this platform, aborting probe\n");
+				return -ENODEV;
+			}
+			dev_info(&pci->dev, "No DSP detected, continuing HDaudio legacy probe\n");
+			break;
+		case SND_SKL_PCI_BIND_LEGACY:
+			dev_info(&pci->dev, "Module parameter forced binding with HDaudio legacy, bypassed detection logic\n");
+			break;
+		case SND_SKL_PCI_BIND_ASOC:
+			dev_info(&pci->dev, "Module parameter forced binding with SKL+ ASoC driver, aborting probe\n");
+			return -ENODEV;
+		default:
+			dev_err(&pci->dev, "invalid value for skl_pci_binding module parameter, ignored\n");
+			break;
+		}
+	}
 
 	if (dev >= SNDRV_CARDS)
 		return -ENODEV;