[vdr] Re: Video Disk Recorder version 1.0.1

["Dr. Werner Fink" <werner@suse.de>]

On Sun, Apr 21, 2002 at 08:19:42PM +0200, Andreas Schultz wrote:
> Hi Klaus,
> 
> On Sunday 21 April 2002 16:59, Klaus Schmidinger wrote:
> > The new version 1.0.1 of the Video Disk Recorder project
> 
> > - Improved thread locking in the ring buffer to avoid possible race
> > conditions under heavy load (thanks to Werner Fink).
> 
> Could you or Werner Fink explain what excatly those changes are supposed to 
> fix?
> I was going over that code before and IMHO is there no race, with a slight 
> change could the code even work completly without locking. There exists only 
> a race between clear and get/put, but that is taken care of by cPlayBuffer.

IMHO the variables head and tail shouldn't be changed without hold
Lock during the changes (ringbuffer.c cRingBufferLinear::Get() and
cRingBufferLinear::Put()).  This may fix the problem seen by some
people (including me) with broken records from Pro7 mainly with AC3 5.1.
Nevertheless even this isn't the reason it doesn't hurt.


      Werner