ALSA: als4000: enable burst mode
Ondrej Zary [Tue, 3 Aug 2010 21:57:05 +0000 (23:57 +0200)]
Enable burst mode to prevent dropouts during high PCI bus usage.
The card is useless in X without this because of dropouts when anything moves
on the screen (at least with PCI VGA card). Enabling this is also recommended
by the datasheet (page 48).

Signed-off-by: Ondrej Zary <linux@rainbow-software.org>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/als4000.c

index 6cf1de8..036a9ba 100644 (file)
@@ -763,9 +763,9 @@ static void snd_als4000_configure(struct snd_sb *chip)
        /* SPECS_PAGE: 39 */
        for (i = ALS4K_GCR91_DMA0_ADDR; i <= ALS4K_GCR96_DMA3_MODE_COUNT; ++i)
                snd_als4k_gcr_write(chip, i, 0);
-       
+       /* enable burst mode to prevent dropouts during high PCI bus usage */
        snd_als4k_gcr_write(chip, ALS4K_GCR99_DMA_EMULATION_CTRL,
-               snd_als4k_gcr_read(chip, ALS4K_GCR99_DMA_EMULATION_CTRL));
+               snd_als4k_gcr_read(chip, ALS4K_GCR99_DMA_EMULATION_CTRL) | 0x04);
        spin_unlock_irq(&chip->reg_lock);
 }