At Thu, 26 Jun 2014 15:37:16 +0800, mengdong.lin@intel.com wrote:

From: Mengdong Lin mengdong.lin@intel.com

For Intel Haswell/Broadwell display HD-A controller, the 24MHz HD-A link BCLK is converted from Core Display Clock (CDCLK): BCLK = CDCLK * M / N And there are two registers EM4 and EM5 to program M, N value respectively. The EM4/EM5 values will be lost and when the display power well is disabled.

BIOS programs CDCLK selected by OEM and EM4/EM5, but BIOS has no idea about display power well on/off at runtime. So the M/N can be wrong if non-default CDCLK is used when the audio controller resumes, which results in an invalid BCLK and abnormal audio playback rate. So this patch saves and restores valid M/N values on controller suspend/resume.

Can this be the cause of bko#74861? https://bugzilla.kernel.org/show_bug.cgi?id=74861

Signed-off-by: Mengdong Lin mengdong.lin@intel.com

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index bb65a124..90a2750 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -580,6 +580,18 @@ static int param_set_xint(const char *val, const struct kernel_param *kp) #define azx_del_card_list(chip) /* NOP */ #endif /* CONFIG_PM */

+static void haswell_save_bclk(struct azx *chip) +{

• chip->bclk_m = azx_readw(chip, EM4);
• chip->bclk_n = azx_readw(chip, EM5);

+}

+static void haswell_restore_bclk(struct azx *chip) +{

• azx_writew(chip, EM4, chip->bclk_m);
• azx_writew(chip, EM5, chip->bclk_n);

+}

This is HSW/BDW specific, so we should avoid adding new fields in struct azx. Instead, define struct hda_intel in hda_intel.c,

struct hda_intel { struct azx chip; /* HSW/BDW display HDA controller to restore BCLK from CDCLK */ unsigned int bclk_m; unsigned int bclk_n; };

then change azx_create() to allocate struct hda_intel instead of struct azx.

struct hda_intel *hda;

hda = kzalloc(sizeof(*hda), GFP_KERNEL); if (!hda) { ... }

chip = &hda->chip; spin_lock_init(&chip->reg_lock); mutex_init(&chip->open_mutex); chip->card = card; ...

and access to bclk_m and bclk_n via cast using container_of().

static void haswell_save_bclk(struct azx *chip) { struct hda_intel *hda = container_of(chip, struct hda_intel, chip); hda->bclk_m = azx_readw(chip, EM4); hda->bclk_n = azx_readw(chip, EM5); }

#if defined(CONFIG_PM_SLEEP) || defined(SUPPORT_VGA_SWITCHEROO) /*

• power management

@@ -606,6 +618,13 @@ static int azx_suspend(struct device *dev) free_irq(chip->irq, chip); chip->irq = -1; }

• /* Save BCLK M/N values before they become invalid in D3.

• * Will test if display power well can be released now.
  

• */
  

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)

• haswell_save_bclk(chip);
  

• if (chip->msi) pci_disable_msi(chip->pci); pci_disable_device(pci);

@@ -625,8 +644,10 @@ static int azx_resume(struct device *dev) if (chip->disabled) return 0;

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) { hda_display_power(true);

• haswell_restore_bclk(chip);
  

• } pci_set_power_state(pci, PCI_D0); pci_restore_state(pci); if (pci_enable_device(pci) < 0) {

@@ -670,8 +691,10 @@ static int azx_runtime_suspend(struct device *dev) azx_stop_chip(chip); azx_enter_link_reset(chip); azx_clear_irq_pending(chip);

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {

• haswell_save_bclk(chip);
  

  hda_display_power(false);
• } return 0;

}

@@ -689,8 +712,10 @@ static int azx_runtime_resume(struct device *dev) if (!(chip->driver_caps & AZX_DCAPS_PM_RUNTIME)) return 0;

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)

• if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) { hda_display_power(true);

• haswell_restore_bclk(chip);
  

• }

  /* Read STATESTS before controller reset */ status = azx_readw(chip, STATESTS);

diff --git a/sound/pci/hda/hda_priv.h b/sound/pci/hda/hda_priv.h index 4a7cb01..1469edb 100644 --- a/sound/pci/hda/hda_priv.h +++ b/sound/pci/hda/hda_priv.h @@ -96,6 +96,14 @@ enum { SDI0, SDI1, SDI2, SDI3, SDO0, SDO1, SDO2, SDO3 }; #define ICH6_REG_SD_BDLPL 0x18 #define ICH6_REG_SD_BDLPU 0x1c

+/* Intel HSW/BDW display HD-A controller Extended Mode registers.

• • EM4 (M value) and EM5 (N Value) are used to convert CDClk (Core Display
• • Clock) to 24MHz BCLK: BCLK = CDCLK * M / N
• • The values will be lost when the display power well is disabled.
• */

+#define ICH6_REG_EM4 0x100c +#define ICH6_REG_EM5 0x1010

These are definitely not for ICH6. Define them rather in hda_intel.c.

I'm going to move more other PCI-controller specific things from hda_priv.h into hda_intel.c, too.

Also, I guess this deserves for Cc to stable, right?

thanks,

Takashi