[PATCH 3.12 006/206] ALSA: hda - restore BCLK M/N value as per CDCLK for HSW/BDW display HDA controller

From: Jiri Slaby
Date: Tue Nov 18 2014 - 10:18:35 EST


From: Mengdong Lin <mengdong.lin@xxxxxxxxx>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit e4d9e513dedb5ac4e166c1053314fa935ddecc8c upstream.

For HSW/BDW display HD-A controller, hda_set_bclk() is defined to set BCLK
by programming the M/N values as per the core display clock (CDCLK) queried from
i915 display driver.

And the audio driver will also set BCLK in azx_first_init() since the display
driver can turn off the shared power in boot phase if only eDP is connected
and M/N values will be lost and must be reprogrammed.

Signed-off-by: Mengdong Lin <mengdong.lin@xxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Takashi Iwai <tiwai@xxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
sound/pci/hda/hda_i915.c | 16 +++++++++++++
sound/pci/hda/hda_i915.h | 2 ++
sound/pci/hda/hda_intel.c | 60 +++++++++++++++++++++++++++++++++++++++++++++--
3 files changed, 76 insertions(+), 2 deletions(-)

diff --git a/sound/pci/hda/hda_i915.c b/sound/pci/hda/hda_i915.c
index 3ea8b980460e..9e136beaa591 100644
--- a/sound/pci/hda/hda_i915.c
+++ b/sound/pci/hda/hda_i915.c
@@ -24,6 +24,7 @@

static int (*get_power)(void);
static int (*put_power)(void);
+static int (*get_cdclk)(void);

int hda_display_power(bool enable)
{
@@ -38,6 +39,13 @@ int hda_display_power(bool enable)
return put_power();
}

+int haswell_get_cdclk(void)
+{
+ if (!get_cdclk)
+ return -EINVAL;
+ return get_cdclk();
+}
+
int hda_i915_init(void)
{
int err = 0;
@@ -55,6 +63,10 @@ int hda_i915_init(void)
return -ENODEV;
}

+ get_cdclk = symbol_request(i915_get_cdclk_freq);
+ if (!get_cdclk) /* may have abnormal BCLK and audio playback rate */
+ snd_printd("hda-i915: get_cdclk symbol get fail\n");
+
snd_printd("HDA driver get symbol successfully from i915 module\n");

return err;
@@ -70,6 +82,10 @@ int hda_i915_exit(void)
symbol_put(i915_release_power_well);
put_power = NULL;
}
+ if (get_cdclk) {
+ symbol_put(i915_get_cdclk_freq);
+ get_cdclk = NULL;
+ }

return 0;
}
diff --git a/sound/pci/hda/hda_i915.h b/sound/pci/hda/hda_i915.h
index bfd835f8f1aa..26869fafe11a 100644
--- a/sound/pci/hda/hda_i915.h
+++ b/sound/pci/hda/hda_i915.h
@@ -18,10 +18,12 @@

#ifdef CONFIG_SND_HDA_I915
int hda_display_power(bool enable);
+int haswell_get_cdclk(void);
int hda_i915_init(void);
int hda_i915_exit(void);
#else
static inline int hda_display_power(bool enable) { return 0; }
+static inline int haswell_get_cdclk(void) { return -EINVAL; }
static inline int hda_i915_init(void)
{
return -ENODEV;
diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 3eb2976824a8..d9a6ef843306 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -748,6 +748,54 @@ static inline void mark_runtime_wc(struct azx *chip, struct azx_dev *azx_dev,
}
#endif

+#ifdef CONFIG_SND_HDA_I915
+/* 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
+
+static void haswell_set_bclk(struct azx *chip)
+{
+ int cdclk_freq;
+ unsigned int bclk_m, bclk_n;
+
+ cdclk_freq = haswell_get_cdclk();
+ if (cdclk_freq < 0)
+ return;
+
+ switch (cdclk_freq) {
+ case 337500:
+ bclk_m = 16;
+ bclk_n = 225;
+ break;
+
+ case 450000:
+ default: /* default CDCLK 450MHz */
+ bclk_m = 4;
+ bclk_n = 75;
+ break;
+
+ case 540000:
+ bclk_m = 4;
+ bclk_n = 90;
+ break;
+
+ case 675000:
+ bclk_m = 8;
+ bclk_n = 225;
+ break;
+ }
+
+ azx_writew(chip, EM4, bclk_m);
+ azx_writew(chip, EM5, bclk_n);
+}
+#else
+static inline void haswell_set_bclk(struct azx *chip) {}
+#endif
+
static int azx_acquire_irq(struct azx *chip, int do_disconnect);
static int azx_send_cmd(struct hda_bus *bus, unsigned int val);
/*
@@ -2951,8 +2999,10 @@ static int azx_resume(struct device *dev)
if (chip->disabled || chip->init_failed)
return 0;

- if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+ if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
hda_display_power(true);
+ haswell_set_bclk(chip);
+ }
pci_set_power_state(pci, PCI_D0);
pci_restore_state(pci);
if (pci_enable_device(pci) < 0) {
@@ -3015,8 +3065,10 @@ 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_set_bclk(chip);
+ }

/* Read STATESTS before controller reset */
status = azx_readw(chip, STATESTS);
@@ -3744,6 +3796,10 @@ static int azx_first_init(struct azx *chip)

/* initialize chip */
azx_init_pci(chip);
+
+ if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+ haswell_set_bclk(chip);
+
azx_init_chip(chip, (probe_only[dev] & 2) == 0);

/* codec detection */
--
2.1.3

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