* HDA driver without interrupt
@ 2012-05-02 12:54 liufc
2012-05-02 19:28 ` Pierre-Louis Bossart
2012-05-03 6:13 ` Clemens Ladisch
0 siblings, 2 replies; 4+ messages in thread
From: liufc @ 2012-05-02 12:54 UTC (permalink / raw)
To: alsa-devel
Hi guys,I'm trying to implement an alsa driver based on the Intel HDA
driver.However due to some hardware defects,I'm not able to use
interrupt.So I wonder whether there is a way to do the job without the
help of interrupt.Can anyone give me a suggestion?
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: HDA driver without interrupt
2012-05-02 12:54 HDA driver without interrupt liufc
@ 2012-05-02 19:28 ` Pierre-Louis Bossart
2012-05-03 6:13 ` Clemens Ladisch
1 sibling, 0 replies; 4+ messages in thread
From: Pierre-Louis Bossart @ 2012-05-02 19:28 UTC (permalink / raw)
To: alsa-devel
On 5/2/2012 7:54 AM, liufc wrote:
> Hi guys,I'm trying to implement an alsa driver based on the Intel HDA
> driver.However due to some hardware defects,I'm not able to use
> interrupt.So I wonder whether there is a way to do the job without the
> help of interrupt.Can anyone give me a suggestion?
What interrupt are you talking about? ALSA has the ability to discard
periodic interrupts but the user-space code needs to explicitly request
this mode (eg PulseAudio/AudioHAL). Regular/legacy apps do need an
interrupt coming from the hardware.
-Pierre
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: HDA driver without interrupt
2012-05-02 12:54 HDA driver without interrupt liufc
2012-05-02 19:28 ` Pierre-Louis Bossart
@ 2012-05-03 6:13 ` Clemens Ladisch
[not found] ` <CAOAAS1z7iA2excEt9cE45CBmQs=XUkigW6+A94zyp2BuRLBBcA@mail.gmail.com>
1 sibling, 1 reply; 4+ messages in thread
From: Clemens Ladisch @ 2012-05-03 6:13 UTC (permalink / raw)
To: liufc; +Cc: alsa-devel
liufc wrote:
> Hi guys,I'm trying to implement an alsa driver based on the Intel HDA
> driver.However due to some hardware defects,I'm not able to use
> interrupt.
How does your hardware work then?
Regards,
Clemens
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: HDA driver without interrupt
[not found] ` <CAOAAS1z7iA2excEt9cE45CBmQs=XUkigW6+A94zyp2BuRLBBcA@mail.gmail.com>
@ 2012-05-03 8:37 ` Clemens Ladisch
0 siblings, 0 replies; 4+ messages in thread
From: Clemens Ladisch @ 2012-05-03 8:37 UTC (permalink / raw)
To: Fanchao Liu; +Cc: alsa-devel
Fanchao Liu wrote:
> It can transfer data via DMA,the problem is I don't know when to
> update hw_ptr and other pointers without interrupt.
Does the hardware have some other means to at least read the current
position?
> I set a timer and call snd_pcm_period_elapsed() every 50ms but get
> underrun error.
With a call to snd_pcm_period_elapsed(), the driver guarantees that the
current position is at or after the next period boundary.
Regards,
Clemens
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2012-05-03 8:33 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-05-02 12:54 HDA driver without interrupt liufc
2012-05-02 19:28 ` Pierre-Louis Bossart
2012-05-03 6:13 ` Clemens Ladisch
[not found] ` <CAOAAS1z7iA2excEt9cE45CBmQs=XUkigW6+A94zyp2BuRLBBcA@mail.gmail.com>
2012-05-03 8:37 ` Clemens Ladisch
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