i915 - disable vsync?

James Stone jamesmstone at gmail.com
Tue Mar 11 04:11:13 PDT 2008

Hi there,

I have an eeepc and I am trying to get the realtime audio daemon jackd
working properly on it. I notice there is some conflict between the
audio and video since moving windows etc. causes audio dropouts
(xruns). The two devices appear to share an interrupt, and there
doesn't seem to be much I can do about that. Paul Davis (author of
Jackd) did not think that sharing an interrupt was necessarily the
cause of xruns, but rather that the graphics driver may be taking
control of the pci bus for too long. Another person on the LAU list
(Lee Revell) suggested that disabling vsync interrupts for the intel
graphics driver might help with this:

"Typically the (userspace X11) video driver tries to write to the
card's command FIFO without first
checking whether it is full.  If the FIFO is full, this will
completely stall the PCI bus until the FIFO drains.  Nothing at all to
do with interrupts."

Could this be a problem with the i915 driver? Is there a way to
disable vsync interrupts for the i915? (I have no clue!)

Best wishes,


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