Re: [PATCH 1/2] drm/i915: Fix gen2 scanout position readout

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Nov 06, 2013 at 10:38:42AM -0200, Rodrigo Vivi wrote:
> I was going to get this for -collector but got a big conflict.

It should be already in. Although as it turns out it's partially
crap. Apparently I hadn't tested the ISR vblank bit behaviour
properly on non-PCH platforms. It doesn't actually work the way
we want, so there are patches in my latest vblank timestamp series
that kill the ISR parts and add a kludge to work around the scanline
counter's silly behaviour.
> 
> 
> On Fri, Oct 11, 2013 at 3:52 PM,  <ville.syrjala@linux.intel.com> wrote:
> > From: Ville Syrjälä <ville.syrjala@linux.intel.com>
> >
> > Gen2 doesn't have the pixelcount register that gen3 and gen4 have.
> > Instead we must use the scanline counter like we do for ctg+.
> >
> > Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_irq.c | 21 +++++++++++++++------
> >  1 file changed, 15 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> > index 63a9642..3c31a2f 100644
> > --- a/drivers/gpu/drm/i915/i915_irq.c
> > +++ b/drivers/gpu/drm/i915/i915_irq.c
> > @@ -592,7 +592,7 @@ static u32 gm45_get_vblank_counter(struct drm_device *dev, int pipe)
> >         return I915_READ(reg);
> >  }
> >
> > -static bool g4x_pipe_in_vblank(struct drm_device *dev, enum pipe pipe)
> > +static bool intel_pipe_in_vblank(struct drm_device *dev, enum pipe pipe)
> >  {
> >         struct drm_i915_private *dev_priv = dev->dev_private;
> >         uint32_t status;
> > @@ -603,7 +603,13 @@ static bool g4x_pipe_in_vblank(struct drm_device *dev, enum pipe pipe)
> >                         I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
> >
> >                 return I915_READ(VLV_ISR) & status;
> > -       } else if (IS_G4X(dev)) {
> > +       } else if (IS_GEN2(dev)) {
> > +               status = pipe == PIPE_A ?
> > +                       I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT :
> > +                       I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
> > +
> > +               return I915_READ16(ISR) & status;
> > +       } else if (INTEL_INFO(dev)->gen < 5) {
> >                 status = pipe == PIPE_A ?
> >                         I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT :
> >                         I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
> > @@ -658,11 +664,14 @@ static int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
> >
> >         ret |= DRM_SCANOUTPOS_VALID | DRM_SCANOUTPOS_ACCURATE;
> >
> > -       if (IS_G4X(dev) || INTEL_INFO(dev)->gen >= 5) {
> > +       if (IS_GEN2(dev) || IS_G4X(dev) || INTEL_INFO(dev)->gen >= 5) {
> >                 /* No obvious pixelcount register. Only query vertical
> >                  * scanout position from Display scan line register.
> >                  */
> > -               position = I915_READ(PIPEDSL(pipe)) & 0x1fff;
> > +               if (IS_GEN2(dev))
> > +                       position = I915_READ(PIPEDSL(pipe)) & DSL_LINEMASK_GEN2;
> > +               else
> > +                       position = I915_READ(PIPEDSL(pipe)) & DSL_LINEMASK_GEN3;
> >
> >                 /*
> >                  * The scanline counter increments at the leading edge
> > @@ -671,7 +680,7 @@ static int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
> >                  * to get a more accurate picture whether we're in vblank
> >                  * or not.
> >                  */
> > -               in_vbl = g4x_pipe_in_vblank(dev, pipe);
> > +               in_vbl = intel_pipe_in_vblank(dev, pipe);
> >                 if ((in_vbl && position == vbl_start - 1) ||
> >                     (!in_vbl && position == vbl_end - 1))
> >                         position = (position + 1) % vtotal;
> > @@ -701,7 +710,7 @@ static int i915_get_crtc_scanoutpos(struct drm_device *dev, int pipe,
> >         else
> >                 position += vtotal - vbl_end;
> >
> > -       if (IS_G4X(dev) || INTEL_INFO(dev)->gen >= 5) {
> > +       if (IS_GEN2(dev) || IS_G4X(dev) || INTEL_INFO(dev)->gen >= 5) {
> >                 *vpos = position;
> >                 *hpos = 0;
> >         } else {
> > --
> > 1.8.1.5
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
> 
> 
> 
> -- 
> Rodrigo Vivi
> Blog: http://blog.vivi.eng.br

-- 
Ville Syrjälä
Intel OTC