Re: [Jack-Devel] Can't bring F/P below 128

On 12/19/2011 12:53 AM, Clemens Ladisch wrote:
> Nikos Chantziaras wrote:
>> I was using a very old and very cheap Soundblaster Live 24-bit PCI.
>> That card uses a CA0106 chip, ... in JACK (using JACK2 now), I could
>> use an F/P setting of 64 without suffering from XRUNs.
>>
>> I recently got a new mainboard, which came with a recent on-board
>> sound chip, an ALC892 from Realtek.
>
> The interesting part is the HDA controller (part of the chipset).
>
>> it's impossible to use 64 F/P on it.  [...] It's not like I get too
>> many XRUNs at 64 and lower, but rather I can't get anything else than
>> just a static buzz noise.
>
> It's likely that the HDA controller uses a larger burst size to save
> power, and that it is too large for this small a period size.  If I've
> read the Intel documentation correctly, is uses packets of at most
> 128 *bytes*, so in theory, it should work.  However, it might be
> worthwhile to try reducing it.  Please try the patch below.
>[...]
> +	azx_sd_writew(azx_dev, SD_FIFOSIZE, 0x1f);
> [...]

Just booted a kernel with the above change applied.  Sounds still works 
fine, but there's no improvement.  Though dmesg now spits this out:

hda-intel: IRQ timing workaround is activated for card #0. Suggest a 
bigger bdl_pos_adj.

1324252219.15218_0.ltw:2,a <jcltsr$f40$3 at dough dot gmane dot org>