[alsa-devel] [PATCH] ALSA: hda: option to enable arbitrary buffer/period sizes
Pierre-Louis Bossart
pierre-louis.bossart at linux.intel.com
Thu Aug 4 17:12:56 CEST 2011
Add new parameter to disable rounding of buffer/period sizes to
multiples of 128 bytes. This is more efficient in terms of memory
access but isn't required by the HDA spec and prevents users from
specifying exact period/buffer sizes. For example for 44.1kHz, a
period size set to 20ms will be rounded to 19.59ms.
Tested and enabled on Intel HDA controllers. Option is disabled by
default for other controllers.
Tested-by: Wu Fengguang <fengguang.wu at intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart at linux.intel.com>
---
Documentation/sound/alsa/ALSA-Configuration.txt | 5 ++
sound/pci/hda/hda_intel.c | 68 ++++++++++++++++++-----
2 files changed, 58 insertions(+), 15 deletions(-)
diff --git a/Documentation/sound/alsa/ALSA-Configuration.txt b/Documentation/sound/alsa/ALSA-Configuration.txt
index 8975701..27126c4 100644
--- a/Documentation/sound/alsa/ALSA-Configuration.txt
+++ b/Documentation/sound/alsa/ALSA-Configuration.txt
@@ -886,6 +886,11 @@ Prior to version 0.9.0rc4 options had a 'snd_' prefix. This was removed.
disable)
power_save_controller - Reset HD-audio controller in power-saving mode
(default = on)
+ align_buffer_size - Force rounding of buffer/period sizes to multiples
+ of 128 bytes. This is more efficient in terms of memory
+ access but isn't required by the HDA spec and prevents
+ users from specifying exact period/buffer sizes.
+ (default = on)
This module supports multiple cards and autoprobe.
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index be69822..2a8bed9 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -116,6 +116,11 @@ module_param(power_save_controller, bool, 0644);
MODULE_PARM_DESC(power_save_controller, "Reset controller in power save mode.");
#endif
+static int align_buffer_size = 1;
+module_param(align_buffer_size, bool, 0644);
+MODULE_PARM_DESC(align_buffer_size,
+ "Force buffer and period sizes to be multiple of 128 bytes.");
+
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("{{Intel, ICH6},"
"{Intel, ICH6M},"
@@ -481,6 +486,7 @@ enum {
#define AZX_DCAPS_NO_64BIT (1 << 18) /* No 64bit address */
#define AZX_DCAPS_SYNC_WRITE (1 << 19) /* sync each cmd write */
#define AZX_DCAPS_OLD_SSYNC (1 << 20) /* Old SSYNC reg for ICH */
+#define AZX_DCAPS_BUFSIZE (1 << 21) /* no buffer size alignment */
/* quirks for ATI SB / AMD Hudson */
#define AZX_DCAPS_PRESET_ATI_SB \
@@ -1599,6 +1605,7 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
struct snd_pcm_runtime *runtime = substream->runtime;
unsigned long flags;
int err;
+ int buff_step;
mutex_lock(&chip->open_mutex);
azx_dev = azx_assign_device(chip, substream);
@@ -1613,10 +1620,25 @@ static int azx_pcm_open(struct snd_pcm_substream *substream)
runtime->hw.rates = hinfo->rates;
snd_pcm_limit_hw_rates(runtime);
snd_pcm_hw_constraint_integer(runtime, SNDRV_PCM_HW_PARAM_PERIODS);
+ if (align_buffer_size)
+ /* constrain buffer sizes to be multiple of 128
+ bytes. This is more efficient in terms of memory
+ access but isn't required by the HDA spec and
+ prevents users from specifying exact period/buffer
+ sizes. For example for 44.1kHz, a period size set
+ to 20ms will be rounded to 19.59ms. */
+ buff_step = 128;
+ else
+ /* Don't enforce steps on buffer sizes, still need to
+ be multiple of 4 bytes (HDA spec). Tested on Intel
+ HDA controllers, may not work on all devices where
+ option needs to be disabled */
+ buff_step = 4;
+
snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_BUFFER_BYTES,
- 128);
+ buff_step);
snd_pcm_hw_constraint_step(runtime, 0, SNDRV_PCM_HW_PARAM_PERIOD_BYTES,
- 128);
+ buff_step);
snd_hda_power_up(apcm->codec);
err = hinfo->ops.open(hinfo, apcm->codec, substream);
if (err < 0) {
@@ -2616,6 +2638,10 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
gcap &= ~ICH6_GCAP_64OK;
}
+ /* disable buffer size rounding to 128-byte multiples if supported */
+ if (chip->driver_caps & AZX_DCAPS_BUFSIZE)
+ align_buffer_size = 0;
+
/* allow 64bit DMA address if supported by H/W */
if ((gcap & ICH6_GCAP_64OK) && !pci_set_dma_mask(pci, DMA_BIT_MASK(64)))
pci_set_consistent_dma_mask(pci, DMA_BIT_MASK(64));
@@ -2817,37 +2843,49 @@ static void __devexit azx_remove(struct pci_dev *pci)
static DEFINE_PCI_DEVICE_TABLE(azx_ids) = {
/* CPT */
{ PCI_DEVICE(0x8086, 0x1c20),
- .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP },
+ .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
+ AZX_DCAPS_BUFSIZE },
/* PBG */
{ PCI_DEVICE(0x8086, 0x1d20),
- .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP },
+ .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
+ AZX_DCAPS_BUFSIZE},
/* Panther Point */
{ PCI_DEVICE(0x8086, 0x1e20),
- .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP },
+ .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_SCH_SNOOP |
+ AZX_DCAPS_BUFSIZE},
/* SCH */
{ PCI_DEVICE(0x8086, 0x811b),
- .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_SCH_SNOOP },
+ .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_SCH_SNOOP |
+ AZX_DCAPS_BUFSIZE},
{ PCI_DEVICE(0x8086, 0x2668),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH6 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH6 */
{ PCI_DEVICE(0x8086, 0x27d8),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH7 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH7 */
{ PCI_DEVICE(0x8086, 0x269a),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ESB2 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ESB2 */
{ PCI_DEVICE(0x8086, 0x284b),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH8 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH8 */
{ PCI_DEVICE(0x8086, 0x293e),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH9 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH9 */
{ PCI_DEVICE(0x8086, 0x293f),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH9 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH9 */
{ PCI_DEVICE(0x8086, 0x3a3e),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH10 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH10 */
{ PCI_DEVICE(0x8086, 0x3a6e),
- .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC }, /* ICH10 */
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_OLD_SSYNC |
+ AZX_DCAPS_BUFSIZE }, /* ICH10 */
/* Generic Intel */
{ PCI_DEVICE(PCI_VENDOR_ID_INTEL, PCI_ANY_ID),
.class = PCI_CLASS_MULTIMEDIA_HD_AUDIO << 8,
.class_mask = 0xffffff,
- .driver_data = AZX_DRIVER_ICH },
+ .driver_data = AZX_DRIVER_ICH | AZX_DCAPS_BUFSIZE },
/* ATI SB 450/600/700/800/900 */
{ PCI_DEVICE(0x1002, 0x437b),
.driver_data = AZX_DRIVER_ATI | AZX_DCAPS_PRESET_ATI_SB },
--
1.7.6
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