[alsa-devel] Intel 82801I (ICH9 Family) HD Audio Controller on a HP dv4 computer

[Takashi Iwai]

At Mon, 15 Dec 2008 11:10:12 +0100 (CET),
Jean-Pierre ANDRE wrote:
> 
> Hi Takashi,
> 
> Than you for your help.
> 
> > 
> > Switching to polling mode is OK and mostly harmless.  But single_cmd
> > is not.  There is a VERY big difference between them.
> 
> Ok.
> 
> > > Probably related is the
> > > fact that I have never seen an IRQ 22. 
> > > 
> > > from proc/interrupts :
> > > 
> > >  22:          0          0   IO-APIC-fasteoi   uhci_hcd:usb6, HDA Intel
> > 
> > Hum, then it must be an interrupt thing.
> > Ask rather ACPI guys.
> > 
> 
> Well, you must be right. Using the irqpoll boot option,
> the sound is correct, and I see four IRQ 20 per second
> (and none when there is no sound).
> 
> 1) Can you confirm an expected IRQ every 250ms ?

This depends on the application set up, i.e. period size.
The value appears reasonable, though.

> The APIC routes PCI INT B to IRQ 22, and alsa is
> expecting IRQ 22. Now I have to get alsa to expect
> IRQ 20 or get APIC to route an appropriate PCI INT
> to IRQ 22....
> 
> 2) Now I get a warning "hda-intel: IRQ timing workaround
>  is activated for card #0. Suggest a bigger bdl_pos_adj."
> 
> What is the range of values I should try ?

Usually bdl_pos_adj=32 should suffice.  You can give more, but it's
rather the system problem in such a case.


Takashi