From: Rander Wang <rander.wang@xxxxxxxxxxxxxxx>
Fix potential DMA hang upon starting playback on devices in HDA mode
on Intel platforms (Gemini Lake/Whiskey Lake/Comet Lake/Ice Lake). It
doesn't affect platforms before Gemini Lake or any Intel device in
non-HDA mode.
The reset value for the LOSDIV register is all output streams valid.
Clear this register to invalidate non-existent streams when the bus
is powered up.
Signed-off-by: Rander Wang <rander.wang@xxxxxxxxxxxxxxx>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@xxxxxxxxxxxxxxx>
---
include/sound/hda_register.h | 3 +++
sound/hda/ext/hdac_ext_controller.c | 5 +++++
2 files changed, 8 insertions(+)
diff --git a/include/sound/hda_register.h b/include/sound/hda_register.h
index 0fd39295b426..057d2a2d0bd0 100644
--- a/include/sound/hda_register.h
+++ b/include/sound/hda_register.h
@@ -264,6 +264,9 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 };
#define AZX_REG_ML_LOUTPAY 0x20
#define AZX_REG_ML_LINPAY 0x30
+/* bit0 is reserved, with BIT(1) mapping to stream1 */
+#define ML_LOSIDV_STREAM_MASK 0xFFFE
+
#define ML_LCTL_SCF_MASK 0xF
#define AZX_MLCTL_SPA (0x1 << 16)
#define AZX_MLCTL_CPA (0x1 << 23)
diff --git a/sound/hda/ext/hdac_ext_controller.c b/sound/hda/ext/hdac_ext_controller.c
index 211ca85acd8c..cfab60d88c92 100644
--- a/sound/hda/ext/hdac_ext_controller.c
+++ b/sound/hda/ext/hdac_ext_controller.c
@@ -270,6 +270,11 @@ int snd_hdac_ext_bus_link_get(struct hdac_bus *bus,
ret = snd_hdac_ext_bus_link_power_up(link);
+ /*
+ * clear the register to invalidate all the output streams
+ */
+ snd_hdac_updatew(link->ml_addr, AZX_REG_ML_LOSIDV,
+ ML_LOSIDV_STREAM_MASK, 0);
/*
* wait for 521usec for codec to report status
* HDA spec section 4.3 - Codec Discovery
--
2.20.1
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