On Sun, Apr 15, 2012 at 03:27:23PM -0400, Michael Shell wrote: > On Sun, 15 Apr 2012 17:50:25 +0100 > Ken Moffat <[email protected]> wrote: > > > i.e. it (slowly: the file is on a local disk) fills the > > buffer, plays the buffer, then waits while it refills the > > buffer. > > I doubt this is the problem, especially on a new machine, > but in the past issues like this were a symptom that DMA > mode was not enabled for the drive(s) in question. Are > you sure the kernel is enabling DMA I/O for the DVD and > the HD? > The disk is SATA, so using libata. All the googling I did in the past suggests DMA is always on with libata for SATA devices (but see below). > BTW, is there a way to check for a drive's DMA mode in > /proc on the newer (/dev/sda using) kernels? (In the old > days it was in /proc/ide, but all that is routed through > the scsi i/o system today.)
I haven't found one. 'hdparm -t' reports > 112 MB/sec for the disk, so I think DMA is definitely in use. However, it only reports between 2 and 3 MB/sec for the DVD drive on /dev/sr0. BUT, that plays fine (with minimal cpu load) if I use vlc without the DVD menus, and similarly plays fine in xine. The wait for the buffer to fill was on the hard disk. ĸen -- das eine Mal als Tragödie, das andere Mal als Farce -- http://linuxfromscratch.org/mailman/listinfo/blfs-support FAQ: http://www.linuxfromscratch.org/blfs/faq.html Unsubscribe: See the above information page
