Re: linux-next: Tree for June 12

[Takashi Iwai]

At Fri, 13 Jun 2008 21:56:31 +0200,
Thomas Meyer wrote:
> 
> Am Donnerstag, den 12.06.2008, 17:53 +1000 schrieb Stephen Rothwell:
> 
> > Changes since next-20080611:
> > 
> 
> Beginning with next-20080612 i've got no sound!
> 
> git bisect told me that, the offending commit is cbc5a5b7d12b4d461bff132f76abc0d4f9f3d8fc (ALSA: hda - Add bdl_pos_adj option):
> 
> I need to add the option bdl_pos_adj=0, to make sound work again, which gives this dmesg entry:
> 
> [   64.697747] hda-intel: IRQ timing workaround is activated for card #0. Suggest a bigger bdl_pos_adj.
> 
> The sound card is:
> 
> $ cat /proc/asound/cards
>  0 [NVidia         ]: HDA-Intel - HDA NVidia
>                       HDA NVidia at 0xfbff0000 irq 21
> 
> 
> $ /sbin/lspci -vv -s 00:06.1
> 00:06.1 Audio device: nVidia Corporation MCP55 High Definition Audio (rev a2)
> 	Subsystem: Micro-Star International Co., Ltd. Unknown device 7250
> 	Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
> 	Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
> 	Latency: 0 (500ns min, 1250ns max)
> 	Interrupt: pin B routed to IRQ 21
> 	Region 0: Memory at fbff0000 (32-bit, non-prefetchable) [size=16K]
> 	Capabilities: <access denied>
> 	Kernel driver in use: HDA Intel
> 	Kernel modules: snd-hda-intel
> 
> What makes me wonder is, that the commit says:
> "    The new option adds the size of the delay in frames.  As default,
>     it's set to 1 -- that is, one sample delay.  Even the hardware is
>     really correct, one sample delay is relatively harmless in comparison
>     with reporting wrong positions."
> 
> Maybe my definition of "harmless" is not "no sound".
> Would you please check this problem?

It was harmless for Intel and ATI hardwares :)
We've not tested NVidia ones.  Good that you caught it fast.

Could you check whether another value, e.g. bdl_pos_adj=32 works?
Since the warning is shown with bdl_pos_adj=0, any position adjustment
is necessary, but likely Nvidia hardware doesn't allow such a fine
sample resolution like bdl_pos_adj=1.


Thanks,

Takashi
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