[alsa-devel] [PATCH 1/1] audio: Fix playback noise with 24/32 bit sample size on BXT
From: "Lu, Han" han.lu@intel.com
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.
Signed-off-by: Lu, Han han.lu@intel.com
diff --git a/include/sound/hda_register.h b/include/sound/hda_register.h index 2ae8812..94dc6a9 100644 --- a/include/sound/hda_register.h +++ b/include/sound/hda_register.h @@ -93,6 +93,9 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 }; #define AZX_REG_HSW_EM4 0x100c #define AZX_REG_HSW_EM5 0x1010
+/* Skylake/Broxton display HD-A controller Extended Mode registers */ +#define AZX_REG_SKL_EM4L 0x1040 + /* PCI space */ #define AZX_PCIREG_TCSEL 0x44
diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c index 22dbfa5..6c2aa4c 100644 --- a/sound/pci/hda/hda_controller.c +++ b/sound/pci/hda/hda_controller.c @@ -27,6 +27,7 @@ #include <linux/module.h> #include <linux/pm_runtime.h> #include <linux/slab.h> +#include <linux/pci.h> #include <sound/core.h> #include <sound/initval.h> #include "hda_controller.h" @@ -34,6 +35,8 @@ #define CREATE_TRACE_POINTS #include "hda_controller_trace.h"
+#define is_broxton(pci) ((pci)->device == 0x5a98) + /* DSP lock helpers */ #define dsp_lock(dev) snd_hdac_dsp_lock(azx_stream(dev)) #define dsp_unlock(dev) snd_hdac_dsp_unlock(azx_stream(dev)) @@ -880,14 +883,35 @@ EXPORT_SYMBOL_GPL(snd_hda_codec_load_dsp_cleanup); #endif /* CONFIG_SND_HDA_DSP_LOADER */
/* + * 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); +} + +/* * reset and start the controller registers */ void azx_init_chip(struct azx *chip, bool full_reset) { + struct pci_dev *pci = chip->pci; + if (snd_hdac_bus_init_chip(azx_bus(chip), full_reset)) { /* correct RINTCNT for CXT */ if (chip->driver_caps & AZX_DCAPS_CTX_WORKAROUND) azx_writew(chip, RINTCNT, 0xc0); + /* reduce dma latency to avoid noise */ + if (is_broxton(pci)) + bxt_reduce_dma_latency(chip); } } EXPORT_SYMBOL_GPL(azx_init_chip);
On Mon, 07 Dec 2015 03:51:49 +0100, han.lu@intel.com wrote:
From: "Lu, Han" han.lu@intel.com
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.
Signed-off-by: Lu, Han han.lu@intel.com
It's a wrong place to patch. hda_controller.c is for generic HD-audio. The Intel-specific code should go into hda_intel.c.
thanks,
Takashi
diff --git a/include/sound/hda_register.h b/include/sound/hda_register.h index 2ae8812..94dc6a9 100644 --- a/include/sound/hda_register.h +++ b/include/sound/hda_register.h @@ -93,6 +93,9 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 }; #define AZX_REG_HSW_EM4 0x100c #define AZX_REG_HSW_EM5 0x1010
+/* Skylake/Broxton display HD-A controller Extended Mode registers */ +#define AZX_REG_SKL_EM4L 0x1040
/* PCI space */ #define AZX_PCIREG_TCSEL 0x44
diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c index 22dbfa5..6c2aa4c 100644 --- a/sound/pci/hda/hda_controller.c +++ b/sound/pci/hda/hda_controller.c @@ -27,6 +27,7 @@ #include <linux/module.h> #include <linux/pm_runtime.h> #include <linux/slab.h> +#include <linux/pci.h> #include <sound/core.h> #include <sound/initval.h> #include "hda_controller.h" @@ -34,6 +35,8 @@ #define CREATE_TRACE_POINTS #include "hda_controller_trace.h"
+#define is_broxton(pci) ((pci)->device == 0x5a98)
/* DSP lock helpers */ #define dsp_lock(dev) snd_hdac_dsp_lock(azx_stream(dev)) #define dsp_unlock(dev) snd_hdac_dsp_unlock(azx_stream(dev)) @@ -880,14 +883,35 @@ EXPORT_SYMBOL_GPL(snd_hda_codec_load_dsp_cleanup); #endif /* CONFIG_SND_HDA_DSP_LOADER */
/*
- 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);
+}
+/*
- reset and start the controller registers
*/ void azx_init_chip(struct azx *chip, bool full_reset) {
- struct pci_dev *pci = chip->pci;
- if (snd_hdac_bus_init_chip(azx_bus(chip), full_reset)) { /* correct RINTCNT for CXT */ if (chip->driver_caps & AZX_DCAPS_CTX_WORKAROUND) azx_writew(chip, RINTCNT, 0xc0);
/* reduce dma latency to avoid noise */if (is_broxton(pci))bxt_reduce_dma_latency(chip);} EXPORT_SYMBOL_GPL(azx_init_chip); -- 2.5.0
-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Monday, December 7, 2015 2:57 PM To: Lu, Han Cc: libin.yang@linux.intel.com; mengdong.lin@linux.intel.com; han.lu@linux.intel.com; alsa-devel@alsa-project.org Subject: Re: [PATCH 1/1] audio: Fix playback noise with 24/32 bit sample size on BXT
On Mon, 07 Dec 2015 03:51:49 +0100, han.lu@intel.com wrote:
From: "Lu, Han" han.lu@intel.com
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.
Signed-off-by: Lu, Han han.lu@intel.com
It's a wrong place to patch. hda_controller.c is for generic HD-audio. The Intel-specific code should go into hda_intel.c.
Sorry. I submitted patch V2, please review, Thanks.
BR, Han
thanks,
Takashi
diff --git a/include/sound/hda_register.h b/include/sound/hda_register.h index 2ae8812..94dc6a9 100644 --- a/include/sound/hda_register.h +++ b/include/sound/hda_register.h @@ -93,6 +93,9 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2,
SDO3 };
#define AZX_REG_HSW_EM4 0x100c #define AZX_REG_HSW_EM5 0x1010
+/* Skylake/Broxton display HD-A controller Extended Mode registers */ +#define AZX_REG_SKL_EM4L 0x1040
/* PCI space */ #define AZX_PCIREG_TCSEL 0x44
diff --git a/sound/pci/hda/hda_controller.c b/sound/pci/hda/hda_controller.c index 22dbfa5..6c2aa4c 100644 --- a/sound/pci/hda/hda_controller.c +++ b/sound/pci/hda/hda_controller.c @@ -27,6 +27,7 @@ #include <linux/module.h> #include <linux/pm_runtime.h> #include <linux/slab.h> +#include <linux/pci.h> #include <sound/core.h> #include <sound/initval.h> #include "hda_controller.h" @@ -34,6 +35,8 @@ #define CREATE_TRACE_POINTS #include "hda_controller_trace.h"
+#define is_broxton(pci) ((pci)->device == 0x5a98)
/* DSP lock helpers */ #define dsp_lock(dev) snd_hdac_dsp_lock(azx_stream(dev)) #define dsp_unlock(dev)
snd_hdac_dsp_unlock(azx_stream(dev))
@@ -880,14 +883,35 @@ EXPORT_SYMBOL_GPL(snd_hda_codec_load_dsp_cleanup); #endif /* CONFIG_SND_HDA_DSP_LOADER */
/*
- 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);
+}
+/*
- reset and start the controller registers
*/ void azx_init_chip(struct azx *chip, bool full_reset) {
- struct pci_dev *pci = chip->pci;
- if (snd_hdac_bus_init_chip(azx_bus(chip), full_reset)) { /* correct RINTCNT for CXT */ if (chip->driver_caps & AZX_DCAPS_CTX_WORKAROUND) azx_writew(chip, RINTCNT, 0xc0);
/* reduce dma latency to avoid noise */if (is_broxton(pci))bxt_reduce_dma_latency(chip);} EXPORT_SYMBOL_GPL(azx_init_chip); -- 2.5.0
participants (3)
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han.luļ¼ intel.com -
Lu, Han
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Takashi Iwai