Hda patch from this day

Alexander Motin mav at FreeBSD.org
Thu Aug 28 02:10:02 UTC 2008

Robert Noland wrote:
> On Tue, 2008-08-26 at 14:09 -0400, Robert Noland wrote:
>> On Tue, 2008-08-26 at 18:03 +0300, Alexander Motin wrote:
>>> Robert Noland wrote:
>>>>> with your 20080825 patch:
>>>>> cat /dev/sndstat:
>>>>> FreeBSD Audio Driver (newpcm: 32bit 2007061600/i386)
>>>>> Installed devices:
>>>>> pcm0: <HDA codec Realtek ALC260 PCM #0> at hdac0 cad 0
>>>>> kld snd_hda [20080825_0100] [GIANT] (0p:0v/1r:1v channels default)
>>>> Giant?  That could be the source of my boot hang.  My root filesys is
>>>> off of usb, which is also Giant, so if your holding the lock...
>>> Actually have no idea what does that mean yet. HDA driver itself locked
>>> without using Giant, and I don't know where it comes from. May be from
>>> sound subsystem, maybe from somewhere else. All I have done is created
>>> child device pcm0 from hdac0 and it appeared in a such way. Probably I
>>> had to dig deeper into device creation to understand this.
>> Sigh, Ok, today my laptop is not hanging...  and mine is showing MPSAFE,
>> so I have no idea what was going on last night.  It is docked right
>> now... I'll un-dock it and see if that effects it, but right now it's
>> all working good.  Sorry for the noise...
> Ok, the dock was the key... When it is not docked, it still hangs.  I'm
> not quite sure what output I can send you to help identify the issue,
> but I'll give it some thought.  If you can think of anything that might
> help, just let me know and I'll gladly send it along.
> I did just see that you updated the patch, so I'll give that a shot and
> see if it happens to resolve the issue.

I was able to reproduce crash on driver unload on i386 system. I have 
found one bug leading to unexpected memory overwrite which probably 
caused this problem.

Also I have found what that [GIANT] on PCM means. [GIANT] flag set there 
  (it must not be in this case) caused problems with OSS and mixer 
locking. I have fixed it also.

Updated patches uploaded.

Alexander Motin

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