1 files changed, 57 insertions, 0 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 1465f6a0e010..83800ac6ebd7 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -361,6 +361,8 @@ enum {
 					((pci)->device == 0x0d0c) || \
 					((pci)->device == 0x160c))
 
+#define IS_BROXTON(pci)	((pci)->device == 0x5a98)
+
 static char *driver_short_names[] = {
 	[AZX_DRIVER_ICH] = "HDA Intel",
 	[AZX_DRIVER_PCH] = "HDA Intel PCH",
@@ -512,15 +514,36 @@ static void azx_init_pci(struct azx *chip)
         }
 }
 
+/*
+ * In BXT-P A0, HD-Audio DMA requests is later than expected,
+ * and makes an audio stream sensitive to system latencies when
+ * 24/32 bits are playing.
+ * Adjusting threshold of DMA fifo to force the DMA request
+ * sooner to improve latency tolerance at the expense of power.
+ */
+static void bxt_reduce_dma_latency(struct azx *chip)
+{
+	u32 val;
+
+	val = azx_readl(chip, SKL_EM4L);
+	val &= (0x3 << 20);
+	azx_writel(chip, SKL_EM4L, val);
+}
+
 static void hda_intel_init_chip(struct azx *chip, bool full_reset)
 {
 	struct hdac_bus *bus = azx_bus(chip);
+	struct pci_dev *pci = chip->pci;
 
 	if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
 		snd_hdac_set_codec_wakeup(bus, true);
 	azx_init_chip(chip, full_reset);
 	if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
 		snd_hdac_set_codec_wakeup(bus, false);
+
+	/* reduce dma latency to avoid noise */
+	if (IS_BROXTON(pci))
+		bxt_reduce_dma_latency(chip);
 }
 
 /* calculate runtime delay from LPIB */
@@ -937,6 +960,36 @@ static int azx_resume(struct device *dev)
 }
 #endif /* CONFIG_PM_SLEEP || SUPPORT_VGA_SWITCHEROO */
 
+#ifdef CONFIG_PM_SLEEP
+/* put codec down to D3 at hibernation for Intel SKL+;
+ * otherwise BIOS may still access the codec and screw up the driver
+ */
+#define IS_SKL(pci) ((pci)->vendor == 0x8086 && (pci)->device == 0xa170)
+#define IS_SKL_LP(pci) ((pci)->vendor == 0x8086 && (pci)->device == 0x9d70)
+#define IS_BXT(pci) ((pci)->vendor == 0x8086 && (pci)->device == 0x5a98)
+#define IS_SKL_PLUS(pci) (IS_SKL(pci) || IS_SKL_LP(pci) || IS_BXT(pci))
+
+static int azx_freeze_noirq(struct device *dev)
+{
+	struct pci_dev *pci = to_pci_dev(dev);
+
+	if (IS_SKL_PLUS(pci))
+		pci_set_power_state(pci, PCI_D3hot);
+
+	return 0;
+}
+
+static int azx_thaw_noirq(struct device *dev)
+{
+	struct pci_dev *pci = to_pci_dev(dev);
+
+	if (IS_SKL_PLUS(pci))
+		pci_set_power_state(pci, PCI_D0);
+
+	return 0;
+}
+#endif /* CONFIG_PM_SLEEP */
+
 #ifdef CONFIG_PM
 static int azx_runtime_suspend(struct device *dev)
 {
@@ -1046,6 +1099,10 @@ static int azx_runtime_idle(struct device *dev)
 
 static const struct dev_pm_ops azx_pm = {
 	SET_SYSTEM_SLEEP_PM_OPS(azx_suspend, azx_resume)
+#ifdef CONFIG_PM_SLEEP
+	.freeze_noirq = azx_freeze_noirq,
+	.thaw_noirq = azx_thaw_noirq,
+#endif
 	SET_RUNTIME_PM_OPS(azx_runtime_suspend, azx_runtime_resume, azx_runtime_idle)
 };