On Wed, Apr 25, 2012 at 06:14:37PM +0100, Chris Wilson wrote: > On Fri, 20 Apr 2012 21:03:35 +0200, Daniel Vetter <daniel.vetter at ffwll.ch> wrote: > > If we try to do that and the scanlines just wouldn't advance, we > > busy-hang the machine holding the modeset mutex. Not great for > > debugging. > > > > References: https://bugzilla.kernel.org/show_bug.cgi?id=43020 > > Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch> > > Reviewer hangs head in shame: > > > + if (wait_for(I915_READ(pipe_dsl_reg) >= vactive, 1000)) > > + DRM_ERROR("timed out waiting for vactive in " > > + "load_detect, scanline: %u\n", > > + I915_READ(pipe_dsl_reg)); > > + if (wait_for((dsl = I915_READ(pipe_dsl_reg)) <= vsample, 1000)) > > + DRM_ERROR("timed out waiting for vsample in " > > + "load_detect, scanline: %u\n", > > + I915_READ(pipe_dsl_reg)); > > wait_for() catches us out everytime we convert and existing while(), > because the predicate is when it stops. Perhaps if we had a wait_until, > but anyway the fix here is: > > if (wait_for(I915_READ(pipe_dsl_reg) < vactive, 1000)) > ... > if (wait_for((dsl = I915_READ(pipe_dsl_reg)) > vsample, 1000)) > ... dinq rectified, it never happened. Thanks for catching this. /me hides in the shame corner -Daniel -- Daniel Vetter Mail: daniel at ffwll.ch Mobile: +41 (0)79 365 57 48
