[ALSA] Fix NM256 hard lock up

Modules: NM256 driver

Treat the nm256 mixer as a write-only device so as to avoid hangs on
initialisation.

Signed-off-by: Florian Schlichting <Florian.Schlichting@gmx.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 96 insertions, 24 deletions

diff --git a/sound/pci/nm256/nm256.c b/sound/pci/nm256/nm256.c
index 3a3ba6f547bc..cc297abc9d11 100644
--- a/sound/pci/nm256/nm256.c
+++ b/sound/pci/nm256/nm256.c
@@ -228,6 +228,7 @@ struct nm256 {
         unsigned int use_cache: 1;      /* use one big coef. table */
         unsigned int reset_workaround: 1; /* Workaround for some laptops to avoid freeze */
         unsigned int reset_workaround_2: 1; /* Extended workaround for some other laptops to avoid freeze */
+        unsigned int in_resume: 1;
 
         int mixer_base;                 /* register offset of ac97 mixer */
         int mixer_status_offset;        /* offset of mixer status reg. */
@@ -242,6 +243,7 @@ struct nm256 {
         struct nm256_stream streams[2];
 
         struct snd_ac97 *ac97;
+        unsigned short *ac97_regs; /* register caches, only for valid regs */
 
         struct snd_pcm *pcm;
 
@@ -1153,23 +1155,63 @@ snd_nm256_ac97_ready(struct nm256 *chip)
         return 0;
 }
 
+/* 
+ * Initial register values to be written to the AC97 mixer.
+ * While most of these are identical to the reset values, we do this
+ * so that we have most of the register contents cached--this avoids
+ * reading from the mixer directly (which seems to be problematic,
+ * probably due to ignorance).
+ */
+
+struct initialValues {
+        unsigned short reg;
+        unsigned short value;
+};
+
+static struct initialValues nm256_ac97_init_val[] =
+{
+        { AC97_MASTER,          0x8000 },
+        { AC97_HEADPHONE,       0x8000 },
+        { AC97_MASTER_MONO,     0x8000 },
+        { AC97_PC_BEEP,         0x8000 },
+        { AC97_PHONE,           0x8008 },
+        { AC97_MIC,             0x8000 },
+        { AC97_LINE,            0x8808 },
+        { AC97_CD,              0x8808 },
+        { AC97_VIDEO,           0x8808 },
+        { AC97_AUX,             0x8808 },
+        { AC97_PCM,             0x8808 },
+        { AC97_REC_SEL,         0x0000 },
+        { AC97_REC_GAIN,        0x0B0B },
+        { AC97_GENERAL_PURPOSE, 0x0000 },
+        { AC97_3D_CONTROL,      0x8000 }, 
+        { AC97_VENDOR_ID1,      0x8384 },
+        { AC97_VENDOR_ID2,      0x7609 },
+};
+
+static int nm256_ac97_idx(unsigned short reg)
+{
+        int i;
+        for (i = 0; i < ARRAY_SIZE(nm256_ac97_init_val); i++)
+                if (nm256_ac97_init_val[i].reg == reg)
+                        return i;
+        return -1;
+}
+
 /*
+ * some nm256 easily crash when reading from mixer registers
+ * thus we're treating it as a write-only mixer and cache the
+ * written values
  */
 static unsigned short
 snd_nm256_ac97_read(struct snd_ac97 *ac97, unsigned short reg)
 {
         struct nm256 *chip = ac97->private_data;
-        int res;
-
-        if (reg >= 128)
-                return 0;
+        int idx = nm256_ac97_idx(reg);
 
-        if (! snd_nm256_ac97_ready(chip))
+        if (idx < 0)
                 return 0;
-        res = snd_nm256_readw(chip, chip->mixer_base + reg);
-        /* Magic delay.  Bleah yucky.  */
-        msleep(1);
-        return res;
+        return chip->ac97_regs[idx];
 }
 
 /* 
@@ -1180,8 +1222,12 @@ snd_nm256_ac97_write(struct snd_ac97 *ac97,
 {
         struct nm256 *chip = ac97->private_data;
         int tries = 2;
+        int idx = nm256_ac97_idx(reg);
         u32 base;
 
+        if (idx < 0)
+                return;
+
         base = chip->mixer_base;
 
         snd_nm256_ac97_ready(chip);
@@ -1190,12 +1236,32 @@ snd_nm256_ac97_write(struct snd_ac97 *ac97,
         while (tries-- > 0) {
                 snd_nm256_writew(chip, base + reg, val);
                 msleep(1);  /* a little delay here seems better.. */
-                if (snd_nm256_ac97_ready(chip))
+                if (snd_nm256_ac97_ready(chip)) {
+                        /* successful write: set cache */
+                        chip->ac97_regs[idx] = val;
                         return;
+                }
         }
         snd_printd("nm256: ac97 codec not ready..\n");
 }
 
+/* static resolution table */
+static struct snd_ac97_res_table nm256_res_table[] = {
+        { AC97_MASTER, 0x1f1f },
+        { AC97_HEADPHONE, 0x1f1f },
+        { AC97_MASTER_MONO, 0x001f },
+        { AC97_PC_BEEP, 0x001f },
+        { AC97_PHONE, 0x001f },
+        { AC97_MIC, 0x001f },
+        { AC97_LINE, 0x1f1f },
+        { AC97_CD, 0x1f1f },
+        { AC97_VIDEO, 0x1f1f },
+        { AC97_AUX, 0x1f1f },
+        { AC97_PCM, 0x1f1f },
+        { AC97_REC_GAIN, 0x0f0f },
+        { } /* terminator */
+};
+
 /* initialize the ac97 into a known state */
 static void
 snd_nm256_ac97_reset(struct snd_ac97 *ac97)
@@ -1213,6 +1279,16 @@ snd_nm256_ac97_reset(struct snd_ac97 *ac97)
                 snd_nm256_writeb(chip, 0x6cc, 0x80);
                 snd_nm256_writeb(chip, 0x6cc, 0x0);
         }
+        if (! chip->in_resume) {
+                int i;
+                for (i = 0; i < ARRAY_SIZE(nm256_ac97_init_val); i++) {
+                        /* preload the cache, so as to avoid even a single
+                         * read of the mixer regs
+                         */
+                        snd_nm256_ac97_write(ac97, nm256_ac97_init_val[i].reg,
+                                             nm256_ac97_init_val[i].value);
+                }
+        }
 }
 
 /* create an ac97 mixer interface */
@@ -1221,32 +1297,25 @@ snd_nm256_mixer(struct nm256 *chip)
 {
         struct snd_ac97_bus *pbus;
         struct snd_ac97_template ac97;
-        int i, err;
+        int err;
         static struct snd_ac97_bus_ops ops = {
                 .reset = snd_nm256_ac97_reset,
                 .write = snd_nm256_ac97_write,
                 .read = snd_nm256_ac97_read,
         };
-        /* looks like nm256 hangs up when unexpected registers are touched... */
-        static int mixer_regs[] = {
-                AC97_MASTER, AC97_HEADPHONE, AC97_MASTER_MONO,
-                AC97_PC_BEEP, AC97_PHONE, AC97_MIC, AC97_LINE, AC97_CD,
-                AC97_VIDEO, AC97_AUX, AC97_PCM, AC97_REC_SEL,
-                AC97_REC_GAIN, AC97_GENERAL_PURPOSE, AC97_3D_CONTROL,
-                /*AC97_EXTENDED_ID,*/
-                AC97_VENDOR_ID1, AC97_VENDOR_ID2,
-                -1
-        };
+
+        chip->ac97_regs = kcalloc(sizeof(short),
+                                  ARRAY_SIZE(nm256_ac97_init_val), GFP_KERNEL);
+        if (! chip->ac97_regs)
+                return -ENOMEM;
 
         if ((err = snd_ac97_bus(chip->card, 0, &ops, NULL, &pbus)) < 0)
                 return err;
 
         memset(&ac97, 0, sizeof(ac97));
         ac97.scaps = AC97_SCAP_AUDIO; /* we support audio! */
-        ac97.limited_regs = 1;
-        for (i = 0; mixer_regs[i] >= 0; i++)
-                set_bit(mixer_regs[i], ac97.reg_accessed);
         ac97.private_data = chip;
+        ac97.res_table = nm256_res_table;
         pbus->no_vra = 1;
         err = snd_ac97_mixer(pbus, &ac97, &chip->ac97);
         if (err < 0)
@@ -1331,6 +1400,7 @@ static int nm256_resume(struct pci_dev *pci)
         int i;
 
         /* Perform a full reset on the hardware */
+        chip->in_resume = 1;
         pci_restore_state(pci);
         pci_enable_device(pci);
         snd_nm256_init_chip(chip);
@@ -1348,6 +1418,7 @@ static int nm256_resume(struct pci_dev *pci)
         }
 
         snd_power_change_state(card, SNDRV_CTL_POWER_D0);
+        chip->in_resume = 0;
         return 0;
 }
 #endif /* CONFIG_PM */
@@ -1372,6 +1443,7 @@ static int snd_nm256_free(struct nm256 *chip)
                 free_irq(chip->irq, chip);
 
         pci_disable_device(chip->pci);
+        kfree(chip->ac97_regs);
         kfree(chip);
         return 0;
 }