Re: strace and ALSA ioctls

[Lee Revell <rlrevell@joe-job.com>]

On Thu, 2006-05-18 at 17:47 +0200, Takashi Iwai wrote:
> At Thu, 18 May 2006 11:41:48 -0400,
> Lee Revell wrote:
> > 
> > I have never seen strace correctly identify a single ALSA ioctl.  This
> > makes debugging a serious PITA.  Is it fixable?
> 
> Quite unlikely.  Some ioctl commands are indeed identical with these
> USBDEVFS_*.  This happened since we didn't care about the collision
> and found it too late.
> 
> In the kernel side this is no problem because the ioctl cmd is bound
> to each driver's ioctl op.  But, from user-space, there is no way to
> distinguish properly.
> 

But for some ioctls it says:

ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon
echo ...}) = 0
ioctl(1, SNDCTL_TMR_TIMEBASE or TCGETS, {B38400 opost isig icanon
echo ...}) = 0

So it seems that strace is aware of some of the collisions but not
others?

Lee



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