ALSA: hda - Fix yet another race of vga_switcheroo registration
The recent fix for vga switcheroo race in commit 128960a9 opened yet
another race. At the time the audio driver starts probing, user may
turn off D-GPU off. But at this moment, the audio driver still
doesn't register the vga switcheroo client, thus the switching isn't
notified. Then the hardware gets off out of sudden, resulting in
invalid reads and lots of "spurious response" error messages.
For solving this situation, the following changes have been done in
this patch:
- Move again vga switcheroo registration to the very early stage of
the probing; this also requires to set pci drvdata properly before
registration
- Introduce the completion to synchronize the driver probe at vga
switcheroo callbacks; this assures that the whole probing finished
before executing the callbacks
Reported-by: Daniel J Blueman <daniel@quora.org>
Tested-by: Daniel J Blueman <daniel@quora.org>
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 4bb52da..22ecadc 100644
--- a/sound/pci/hda/hda_intel.c
+++ b/sound/pci/hda/hda_intel.c
@@ -49,6 +49,7 @@
#include <linux/pm_runtime.h>
#include <linux/clocksource.h>
#include <linux/time.h>
+#include <linux/completion.h>
#ifdef CONFIG_X86
/* for snoop control */
@@ -469,6 +470,7 @@
/* locks */
spinlock_t reg_lock;
struct mutex open_mutex;
+ struct completion probe_wait;
/* streams (x num_streams) */
struct azx_dev *azx_dev;
@@ -2745,6 +2747,7 @@
struct azx *chip = card->private_data;
bool disabled;
+ wait_for_completion(&chip->probe_wait);
if (chip->init_failed)
return;
@@ -2790,6 +2793,7 @@
struct snd_card *card = pci_get_drvdata(pci);
struct azx *chip = card->private_data;
+ wait_for_completion(&chip->probe_wait);
if (chip->init_failed)
return false;
if (chip->disabled || !chip->bus)
@@ -2851,6 +2855,9 @@
azx_notifier_unregister(chip);
+ chip->init_failed = 1; /* to be sure */
+ complete(&chip->probe_wait);
+
if (use_vga_switcheroo(chip)) {
if (chip->disabled && chip->bus)
snd_hda_unlock_devices(chip->bus);
@@ -3156,6 +3163,7 @@
INIT_LIST_HEAD(&chip->pcm_list);
INIT_LIST_HEAD(&chip->list);
init_vga_switcheroo(chip);
+ init_completion(&chip->probe_wait);
chip->position_fix[0] = chip->position_fix[1] =
check_position_fix(chip, position_fix[dev]);
@@ -3183,26 +3191,6 @@
}
}
- if (check_hdmi_disabled(pci)) {
- snd_printk(KERN_INFO SFX "VGA controller for %s is disabled\n",
- pci_name(pci));
- if (use_vga_switcheroo(chip)) {
- snd_printk(KERN_INFO SFX "Delaying initialization\n");
- chip->disabled = true;
- goto ok;
- }
- kfree(chip);
- pci_disable_device(pci);
- return -ENXIO;
- }
-
- err = azx_first_init(chip);
- if (err < 0) {
- azx_free(chip);
- return err;
- }
-
- ok:
err = snd_device_new(card, SNDRV_DEV_LOWLEVEL, chip, &ops);
if (err < 0) {
snd_printk(KERN_ERR SFX "Error creating device [card]!\n");
@@ -3447,7 +3435,29 @@
if (err < 0)
goto out_free;
card->private_data = chip;
+
+ pci_set_drvdata(pci, card);
+
+ err = register_vga_switcheroo(chip);
+ if (err < 0) {
+ snd_printk(KERN_ERR SFX
+ "Error registering VGA-switcheroo client\n");
+ goto out_free;
+ }
+
+ if (check_hdmi_disabled(pci)) {
+ snd_printk(KERN_INFO SFX "VGA controller for %s is disabled\n",
+ pci_name(pci));
+ snd_printk(KERN_INFO SFX "Delaying initialization\n");
+ chip->disabled = true;
+ }
+
probe_now = !chip->disabled;
+ if (probe_now) {
+ err = azx_first_init(chip);
+ if (err < 0)
+ goto out_free;
+ }
#ifdef CONFIG_SND_HDA_PATCH_LOADER
if (patch[dev] && *patch[dev]) {
@@ -3468,23 +3478,16 @@
goto out_free;
}
- pci_set_drvdata(pci, card);
-
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++;
+ complete(&chip->probe_wait);
return 0;
out_free:
snd_card_free(card);
+ pci_set_drvdata(pci, NULL);
return err;
}