[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>

diff --git a/sound/pci/nm256/nm256.c b/sound/pci/nm256/nm256.c
index 3a3ba6f..cc297ab 100644 (file)
--- 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;
 }