At Fri, 9 May 2014 10:08:19 +0000, Lin, Mengdong wrote:
Hi,
We found the Broadwell HDMI audio regression is introduced by this patch:
commit dcb32ecd9a533f47ab652c5c5680bc50a7a822cd Author: Anssi Hannula anssi.hannula@iki.fi Date: Tue Apr 8 12:36:42 2014 +0300 ALSA: hda - Do not assign streams in reverse order
We'll further check the root cause. Since this patch seems only affect the stream ID. Actually Intel GPU tool only find the stream ID is changed by this patch.
In addition, Haswell HDMI audio is not affected and works well. It seems there is HW behavior difference between HSW and BDW.
Thanks for spotting out!
This sounds like a weird hardware bug of BDW. If any, we'd need to introduce a flag indicating flipping this lookup behavior depending on the chip.
Takashi
Thanks Mengdong
-----Original Message----- From: David Henningsson [mailto:david.henningsson@canonical.com] Sent: Friday, May 09, 2014 12:06 AM To: Yang, Libin; Takashi Iwai Cc: Lin, Mengdong; alsa-devel@alsa-project.org; Pierre-Louis Bossart Subject: Re: [alsa-devel] [PATCH] ALSA: hda - using POS_FIX_LPIB on Broadwell HDMI Audio
On 2014-05-08 09:58, Yang, Libin wrote:
Hi Takashi,
I tested the non-snoop mode. It's worse than snoop mode. Only noise can be
heard if using non-snoop mode.
I add the print in the function azx_position_ok(). The below is the dmesg: [ 119.509631] <0>posbuf: 26368, lpib: 16320, wallclk: 2330325 [ 119.509674] snd_hda_intel 0000:00:03.0: IRQ timing workaround is
activated for card #0. Suggest a bigger bdl_pos_adj.
[ 119.509683] <0>posbuf: 26368, lpib: 16332, wallclk: 2331659 [ 119.515467] <0>posbuf: 28224, lpib: 17444, wallclk: 2470504 [ 119.523460] <0>posbuf: 30592, lpib: 18976, wallclk: 2662403 [ 119.531431] <0>posbuf: 32128, lpib: 20508, wallclk: 2853751 [ 119.594932] snd_hda_intel 0000:00:03.0: Unstable LPIB (20416 >= 16384); disabling LPIB delay counting
This looks quite bad - is it not a hardware bug if LPIB > CBL (CBL should be 16384 in this case)?
-- David Henningsson, Canonical Ltd. https://launchpad.net/~diwic