ALSA: hda - Fix registration race of VGA switcheroo

Delay the registration of VGA switcheroo client to the end of the
probing.  Otherwise a too quick switching may result in Oops during
probing.

Also add the check of the return value from snd_hda_lock_devices().

Reported-and-tested-by: Daniel J Blueman <daniel@quora.org>
Cc: <stable@vger.kernel.org> [v3.5+]
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c
index 69810b21f7f4e69ce052e69659f9f97205f0ecf3..ecf277506ad1b25110ec43e21d5948430f0021a0 100644 (file)
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -501,6 +501,7 @@ struct azx {
 
        /* VGA-switcheroo setup */
        unsigned int use_vga_switcheroo:1;
+       unsigned int vga_switcheroo_registered:1;
        unsigned int init_failed:1; /* delayed init failed */
        unsigned int disabled:1; /* disabled by VGA-switcher */
 
@@ -2640,7 +2641,9 @@ static void azx_vs_set_state(struct pci_dev *pci,
                if (disabled) {
                        azx_suspend(&pci->dev);
                        chip->disabled = true;
-                       snd_hda_lock_devices(chip->bus);
+                       if (snd_hda_lock_devices(chip->bus))
+                               snd_printk(KERN_WARNING SFX
+                                          "Cannot lock devices!\n");
                } else {
                        snd_hda_unlock_devices(chip->bus);
                        chip->disabled = false;
@@ -2683,14 +2686,20 @@ static const struct vga_switcheroo_client_ops azx_vs_ops = {
 
 static int __devinit register_vga_switcheroo(struct azx *chip)
 {
+       int err;
+
        if (!chip->use_vga_switcheroo)
                return 0;
        /* FIXME: currently only handling DIS controller
         * is there any machine with two switchable HDMI audio controllers?
         */
-       return vga_switcheroo_register_audio_client(chip->pci, &azx_vs_ops,
+       err = vga_switcheroo_register_audio_client(chip->pci, &azx_vs_ops,
                                                    VGA_SWITCHEROO_DIS,
                                                    chip->bus != NULL);
+       if (err < 0)
+               return err;
+       chip->vga_switcheroo_registered = 1;
+       return 0;
 }
 #else
 #define init_vga_switcheroo(chip)              /* NOP */
@@ -2712,7 +2721,8 @@ static int azx_free(struct azx *chip)
        if (use_vga_switcheroo(chip)) {
                if (chip->disabled && chip->bus)
                        snd_hda_unlock_devices(chip->bus);
-               vga_switcheroo_unregister_client(chip->pci);
+               if (chip->vga_switcheroo_registered)
+                       vga_switcheroo_unregister_client(chip->pci);
        }
 
        if (chip->initialized) {
@@ -3060,14 +3070,6 @@ static int __devinit azx_create(struct snd_card *card, struct pci_dev *pci,
        }
 
  ok:
-       err = register_vga_switcheroo(chip);
-       if (err < 0) {
-               snd_printk(KERN_ERR SFX
-                          "Error registering VGA-switcheroo client\n");
-               azx_free(chip);
-               return err;
-       }
-
        err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
        if (err < 0) {
                snd_printk(KERN_ERR SFX "Error creating device [card]!\n");
@@ -3338,6 +3340,13 @@ static int __devinit azx_probe(struct pci_dev *pci,
        if (pci_dev_run_wake(pci))
                pm_runtime_put_noidle(&pci->dev);
 
+       err = register_vga_switcheroo(chip);
+       if (err < 0) {
+               snd_printk(KERN_ERR SFX
+                          "Error registering VGA-switcheroo client\n");
+               goto out_free;
+       }
+
        dev++;
        return 0;