diff options
| author | Takashi Iwai <tiwai@suse.de> | 2008-02-22 18:36:22 +0100 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2008-02-22 14:20:08 -0800 |
| commit | 90a5ad52bf2ce54aa7153735dc4488f00c050e54 (patch) | |
| tree | bbb7ae0ce83e538382ff2bba4e6ad5d6ff5d7357 /sound/pci | |
| parent | 92eed66d5e612216369b27330ac43f6f094d0130 (diff) | |
| download | lwn-90a5ad52bf2ce54aa7153735dc4488f00c050e54.tar.gz lwn-90a5ad52bf2ce54aa7153735dc4488f00c050e54.zip | |
[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/pci')
| -rw-r--r-- | sound/pci/hda/hda_intel.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index 56f8a3050751..a1098bb875de 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? */ |