[PATCH 3.15 66/66] ALSA: hda - restore BCLK M/N values when resuming HSW/BDW display controller

Greg Kroah-Hartman
2014-07-04T22:53:58Z

From: Mengdong Lin <mengdong.lin@intel.com>

commit a07187c992be945ab561b370cbb49cfd72064c3c upstream.

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.

And 'struct hda_intel' is defined to contain standard HD-A 'struct azx' and
Intel specific fields, as Takashi suggested.

Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
sound/pci/hda/hda_intel.c | 65 +++++++++++++++++++++++++++++++++++++++++-----
1 file changed, 58 insertions(+), 7 deletions(-)

--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -282,6 +282,24 @@ static char *driver_short_names[] = {
[AZX_DRIVER_GENERIC] = "HD-Audio Generic",
};

+
+/* Intel HSW/BDW display HDA 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
+
+struct hda_intel {
+ struct azx chip;
+
+ /* HSW/BDW display HDA controller to restore BCLK from CDCLK */
+ unsigned int bclk_m;
+ unsigned int bclk_n;
+};
+
+
#ifdef CONFIG_X86
static void __mark_pages_wc(struct azx *chip, struct snd_dma_buffer *dmab, bool on)
{
@@ -574,6 +592,22 @@ static int param_set_xint(const char *va
#define azx_del_card_list(chip) /* NOP */
#endif /* CONFIG_PM */

+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);
+}
+
+static void haswell_restore_bclk(struct azx *chip)
+{
+ struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
+
+ azx_writew(chip, EM4, hda->bclk_m);
+ azx_writew(chip, EM5, hda->bclk_n);
+}
+
#if defined(CONFIG_PM_SLEEP) || defined(SUPPORT_VGA_SWITCHEROO)
/*
* power management
@@ -600,6 +634,13 @@ static int azx_suspend(struct device *de
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);
@@ -619,8 +660,10 @@ 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) {
@@ -664,8 +707,10 @@ static int azx_runtime_suspend(struct de
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;
}

@@ -683,8 +728,10 @@ static int azx_runtime_resume(struct 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);
@@ -877,6 +924,8 @@ static int register_vga_switcheroo(struc
static int azx_free(struct azx *chip)
{
struct pci_dev *pci = chip->pci;
+ struct hda_intel *hda = container_of(chip, struct hda_intel, chip);
+
int i;

if ((chip->driver_caps & AZX_DCAPS_PM_RUNTIME)
@@ -924,7 +973,7 @@ static int azx_free(struct azx *chip)
hda_display_power(false);
hda_i915_exit();
}
- kfree(chip);
+ kfree(hda);

return 0;
}
@@ -1168,6 +1217,7 @@ static int azx_create(struct snd_card *c
static struct snd_device_ops ops = {
.dev_free = azx_dev_free,
};
+ struct hda_intel *hda;
struct azx *chip;
int err;

@@ -1177,13 +1227,14 @@ static int azx_create(struct snd_card *c
if (err < 0)
return err;

- chip = kzalloc(sizeof(*chip), GFP_KERNEL);
- if (!chip) {
- dev_err(card->dev, "Cannot allocate chip\n");
+ hda = kzalloc(sizeof(*hda), GFP_KERNEL);
+ if (!hda) {
+ dev_err(card->dev, "Cannot allocate hda\n");
pci_disable_device(pci);
return -ENOMEM;
}

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