[alsa-devel] als4000: enable burst mode

[Ondrej Zary]

On Wednesday 04 August 2010 21:31:32 Takashi Iwai wrote:
> At Wed, 4 Aug 2010 21:08:14 +0200,
>
> Ondrej Zary wrote:
> > On Wednesday 04 August 2010 07:43:44 Takashi Iwai wrote:
> > > At Tue, 3 Aug 2010 23:57:05 +0200,
> > >
> > > Ondrej Zary wrote:
> > > > 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 at rainbow-software.org>
> > >
> > > Applied now.  Thanks.
> >
> > My previous patch assumed that the DMA mode (represented by 3 lowest bits
> > of ALS4K_GCR99_DMA_EMULATION_CTRL register) is set to the default value
> > 0. If that's not the case, it might result in invalid mode to be set.
> > This v2 patch fixes this potential problem.
> >
> > Signed-off-by: Ondrej Zary <linux at rainbow-software.org>
>
> As the previous patch was already applied, could you give the
> incremental change?

Of course, sorry for that.


My previous patch assumed that the DMA mode (represented by 3 lowest bits of 
ALS4K_GCR99_DMA_EMULATION_CTRL register) is set to the default value 0. If 
that's not the case, it might result in invalid mode to be set.
This patch fixes this potential problem.

Signed-off-by: Ondrej Zary <linux at rainbow-software.org>

--- linux-2.6.35-rc3-/sound/pci/als4000.c	2010-08-04 21:53:48.000000000 +0200
+++ linux-2.6.35-rc3/sound/pci/als4000.c	2010-08-04 20:57:00.000000000 +0200
@@ -765,7 +765,7 @@ static void snd_als4000_configure(struct
 		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) | 0x04);
+		(snd_als4k_gcr_read(chip, ALS4K_GCR99_DMA_EMULATION_CTRL) & ~0x07) | 0x04);
 	spin_unlock_irq(&chip->reg_lock);
 }
 



-- 
Ondrej Zary