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authorTakashi Iwai <tiwai@suse.de>2008-02-22 18:36:22 +0100
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-22 14:20:08 -0800
commit90a5ad52bf2ce54aa7153735dc4488f00c050e54 (patch)
treebbb7ae0ce83e538382ff2bba4e6ad5d6ff5d7357 /sound
parent92eed66d5e612216369b27330ac43f6f094d0130 (diff)
downloadlinux-2.6.34-ux500-90a5ad52bf2ce54aa7153735dc4488f00c050e54.tar.gz
[ALSA] HDA - enable snoop on SCH
This patch enables snoop on Intel SCH chipset, eliminating static during playback. Signed-off-by: Tobin Davis <tdavis@dsl-only.net> Signed-off-by: Takashi Iwai <tiwai@suse.de> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'sound')
-rw-r--r--sound/pci/hda/hda_intel.c21
1 files changed, 21 insertions, 0 deletions
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 56f8a305075..a1098bb875d 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -275,6 +275,11 @@ enum {
#define NVIDIA_HDA_TRANSREG_ADDR 0x4e
#define NVIDIA_HDA_ENABLE_COHBITS 0x0f
+/* Defines for Intel SCH HDA snoop control */
+#define INTEL_SCH_HDA_DEVC 0x78
+#define INTEL_SCH_HDA_DEVC_NOSNOOP (0x1<<11)
+
+
/*
*/
@@ -868,6 +873,8 @@ static void update_pci_byte(struct pci_dev *pci, unsigned int reg,
static void azx_init_pci(struct azx *chip)
{
+ unsigned short snoop;
+
/* Clear bits 0-2 of PCI register TCSEL (at offset 0x44)
* TCSEL == Traffic Class Select Register, which sets PCI express QOS
* Ensuring these bits are 0 clears playback static on some HD Audio
@@ -888,6 +895,19 @@ static void azx_init_pci(struct azx *chip)
NVIDIA_HDA_TRANSREG_ADDR,
0x0f, NVIDIA_HDA_ENABLE_COHBITS);
break;
+ case AZX_DRIVER_SCH:
+ pci_read_config_word(chip->pci, INTEL_SCH_HDA_DEVC, &snoop);
+ if (snoop & INTEL_SCH_HDA_DEVC_NOSNOOP) {
+ pci_write_config_word(chip->pci, INTEL_SCH_HDA_DEVC, \
+ snoop & (~INTEL_SCH_HDA_DEVC_NOSNOOP));
+ pci_read_config_word(chip->pci,
+ INTEL_SCH_HDA_DEVC, &snoop);
+ snd_printdd("HDA snoop disabled, enabling ... %s\n",\
+ (snoop & INTEL_SCH_HDA_DEVC_NOSNOOP) \
+ ? "Failed" : "OK");
+ }
+ break;
+
}
}
@@ -1040,6 +1060,7 @@ static int azx_setup_controller(struct azx *chip, struct azx_dev *azx_dev)
static unsigned int azx_max_codecs[] __devinitdata = {
[AZX_DRIVER_ICH] = 3,
+ [AZX_DRIVER_SCH] = 3,
[AZX_DRIVER_ATI] = 4,
[AZX_DRIVER_ATIHDMI] = 4,
[AZX_DRIVER_VIA] = 3, /* FIXME: correct? */