ALSA: hda - Add power-welll support for haswell HDA

For Intel Haswell chip, HDA controller and codec have
power well dependency from GPU side. This patch added support
to request/release power well in audio driver. Power save
feature should be enabled to get runtime power saving.

There's deadlock when request_module(i915) in azx_probe.
It looks like:
device_lock(audio pci device) -> azx_probe -> module_request
(or symbol_request) -> modprobe (userspace) -> i915 init ->
drm_pci_init -> pci_register_driver -> bus_add_driver -> driver_attach ->
which in turn tries all locks on pci bus, and when it tries the one on the
audio device, it will deadlock.

This patch introduce a work to store remaining probe stuff, and let
request_module run in safe work context.

Signed-off-by: Wang Xingchao <xingchao.wang@linux.intel.com>
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Reviewed-by: Liam Girdwood <liam.r.girdwood@intel.com>
Reviewed-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

1 files changed, 57 insertions, 3 deletions

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 3e3126ba8276..35e9f8b010a7 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -62,6 +62,7 @@
 #include <linux/vga_switcheroo.h>
 #include <linux/firmware.h>
 #include "hda_codec.h"
+#include "hda_i915.h"
 
 
 static int index[SNDRV_CARDS] = SNDRV_DEFAULT_IDX;
@@ -541,6 +542,10 @@ struct azx {
         /* for pending irqs */
         struct work_struct irq_pending_work;
 
+#ifdef CONFIG_SND_HDA_I915
+        struct work_struct probe_work;
+#endif
+
         /* reboot notifier (for mysterious hangup problem at power-down) */
         struct notifier_block reboot_notifier;
 
@@ -594,6 +599,7 @@ enum {
 #define AZX_DCAPS_4K_BDLE_BOUNDARY (1 << 23)    /* BDLE in 4k boundary */
 #define AZX_DCAPS_COUNT_LPIB_DELAY  (1 << 25)   /* Take LPIB as delay */
 #define AZX_DCAPS_PM_RUNTIME    (1 << 26)       /* runtime PM support */
+#define AZX_DCAPS_I915_POWERWELL (1 << 27)      /* HSW i915 power well support */
 
 /* quirks for Intel PCH */
 #define AZX_DCAPS_INTEL_PCH_NOPM \
@@ -2900,6 +2906,8 @@ static int azx_suspend(struct device *dev)
         pci_disable_device(pci);
         pci_save_state(pci);
         pci_set_power_state(pci, PCI_D3hot);
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+                hda_display_power(false);
         return 0;
 }
 
@@ -2912,6 +2920,8 @@ static int azx_resume(struct device *dev)
         if (chip->disabled)
                 return 0;
 
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+                hda_display_power(true);
         pci_set_power_state(pci, PCI_D0);
         pci_restore_state(pci);
         if (pci_enable_device(pci) < 0) {
@@ -2944,6 +2954,8 @@ static int azx_runtime_suspend(struct device *dev)
 
         azx_stop_chip(chip);
         azx_clear_irq_pending(chip);
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+                hda_display_power(false);
         return 0;
 }
 
@@ -2952,6 +2964,8 @@ static int azx_runtime_resume(struct device *dev)
         struct snd_card *card = dev_get_drvdata(dev);
         struct azx *chip = card->private_data;
 
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)
+                hda_display_power(true);
         azx_init_pci(chip);
         azx_init_chip(chip, 1);
         return 0;
@@ -3176,6 +3190,10 @@ static int azx_free(struct azx *chip)
         if (chip->fw)
                 release_firmware(chip->fw);
 #endif
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
+                hda_display_power(false);
+                hda_i915_exit();
+        }
         kfree(chip);
 
         return 0;
@@ -3401,6 +3419,13 @@ static void azx_check_snoop_available(struct azx *chip)
         }
 }
 
+#ifdef CONFIG_SND_HDA_I915
+static void azx_probe_work(struct work_struct *work)
+{
+        azx_probe_continue(container_of(work, struct azx, probe_work));
+}
+#endif
+
 /*
  * constructor
  */
@@ -3476,7 +3501,13 @@ static int azx_create(struct snd_card *card, struct pci_dev *pci,
                 return err;
         }
 
+#ifdef CONFIG_SND_HDA_I915
+        /* continue probing in work context as may trigger request module */
+        INIT_WORK(&chip->probe_work, azx_probe_work);
+#endif
+
         *rchip = chip;
+
         return 0;
 }
 
@@ -3747,6 +3778,16 @@ static int azx_probe(struct pci_dev *pci,
         }
 #endif /* CONFIG_SND_HDA_PATCH_LOADER */
 
+        /* continue probing in work context, avoid request_module deadlock */
+        if (probe_now && (chip->driver_caps & AZX_DCAPS_I915_POWERWELL)) {
+#ifdef CONFIG_SND_HDA_I915
+                probe_now = false;
+                schedule_work(&chip->probe_work);
+#else
+                snd_printk(KERN_ERR SFX "Haswell must build in CONFIG_SND_HDA_I915\n");
+#endif
+        }
+
         if (probe_now) {
                 err = azx_probe_continue(chip);
                 if (err < 0)
@@ -3769,6 +3810,16 @@ static int azx_probe_continue(struct azx *chip)
         int dev = chip->dev_index;
         int err;
 
+        /* Request power well for Haswell HDA controller and codec */
+        if (chip->driver_caps & AZX_DCAPS_I915_POWERWELL) {
+                err = hda_i915_init();
+                if (err < 0) {
+                        snd_printk(KERN_ERR SFX "Error request power-well from i915\n");
+                        goto out_free;
+                }
+                hda_display_power(true);
+        }
+
         err = azx_first_init(chip);
         if (err < 0)
                 goto out_free;
@@ -3863,11 +3914,14 @@ static DEFINE_PCI_DEVICE_TABLE(azx_ids) = {
           .driver_data = AZX_DRIVER_PCH | AZX_DCAPS_INTEL_PCH },
         /* Haswell */
         { PCI_DEVICE(0x8086, 0x0a0c),
-          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH },
+          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH |
+          AZX_DCAPS_I915_POWERWELL },
         { PCI_DEVICE(0x8086, 0x0c0c),
-          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH },
+          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH |
+          AZX_DCAPS_I915_POWERWELL },
         { PCI_DEVICE(0x8086, 0x0d0c),
-          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH },
+          .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH |
+          AZX_DCAPS_I915_POWERWELL },
         /* 5 Series/3400 */
         { PCI_DEVICE(0x8086, 0x3b56),
           .driver_data = AZX_DRIVER_SCH | AZX_DCAPS_INTEL_PCH_NOPM },