Re: [PATCH v3] drm/i915: Generalize drain latency computation

Daniel Vetter
2014-08-06T19:48:51Z

On Wed, Aug 06, 2014 at 06:07:12PM +0300, Ville Syrjälä wrote:
> On Thu, Aug 07, 2014 at 01:58:24AM +0530, Gajanan Bhat wrote:
> > Modify drain latency computation to use it for any plane. Same function can be
> > used for primary, cursor and sprite planes.
> >
> > v2: Adressed review comments by Imre and Ville.
> > - Moved clock round up in separate patch
> > - Added WARN check for clock and pixel size
> > - Simplified bit masking
> > - Use cursor_base instead of reg read
> >
> > v3: Changed to bitwise shorthand operator for plane_dl assignment.
> >
> > Signed-off-by: Gajanan Bhat <gajanan.bhat@intel.com>
>
> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

Pulled in these two patches.
-Danil

>
> > ---
> > drivers/gpu/drm/i915/i915_reg.h | 1 +
> > drivers/gpu/drm/i915/intel_pm.c | 87 ++++++++++++++++++++++-----------------
> > 2 files changed, 51 insertions(+), 37 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 187f862..08916df 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -4009,6 +4009,7 @@ enum punit_power_well {
> > #define DDL_PLANE_PRECISION_64 (1<<7)
> > #define DDL_PLANE_PRECISION_32 (0<<7)
> > #define DDL_PLANE_SHIFT 0
> > +#define DRAIN_LATENCY_MASK 0x7f
> >
> > /* FIFO watermark sizes etc */
> > #define G4X_FIFO_LINE_SIZE 64
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> > index ba8dfeb..cabea4b 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -1277,33 +1277,24 @@ static bool g4x_compute_srwm(struct drm_device *dev,
> > display, cursor);
> > }
> >
> > -static bool vlv_compute_drain_latency(struct drm_device *dev,
> > - int plane,
> > - int *plane_prec_mult,
> > - int *plane_dl,
> > - int *cursor_prec_mult,
> > - int *cursor_dl)
> > +static bool vlv_compute_drain_latency(struct drm_crtc *crtc,
> > + int pixel_size,
> > + int *prec_mult,
> > + int *drain_latency)
> > {
> > - struct drm_crtc *crtc;
> > - int clock, pixel_size;
> > int entries;
> > + int clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
> >
> > - crtc = intel_get_crtc_for_plane(dev, plane);
> > - if (!intel_crtc_active(crtc))
> > + if (WARN(clock == 0, "Pixel clock is zero!\n"))
> > return false;
> >
> > - clock = to_intel_crtc(crtc)->config.adjusted_mode.crtc_clock;
> > - pixel_size = crtc->primary->fb->bits_per_pixel / 8; /* BPP */
> > + if (WARN(pixel_size == 0, "Pixel size is zero!\n"))
> > + return false;
> >
> > entries = (clock / 1000) * pixel_size;
> > - *plane_prec_mult = (entries > 128) ?
> > - DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
> > - *plane_dl = (64 * (*plane_prec_mult) * 4) / entries;
> > -
> > - entries = (clock / 1000) * 4; /* BPP is always 4 for cursor */
> > - *cursor_prec_mult = (entries > 128) ?
> > - DRAIN_LATENCY_PRECISION_64 : DRAIN_LATENCY_PRECISION_32;
> > - *cursor_dl = (64 * (*cursor_prec_mult) * 4) / entries;
> > + *prec_mult = (entries > 128) ? DRAIN_LATENCY_PRECISION_64 :
> > + DRAIN_LATENCY_PRECISION_32;
> > + *drain_latency = (64 * (*prec_mult) * 4) / entries;
> >
> > return true;
> > }
> > @@ -1318,24 +1309,46 @@ static bool vlv_compute_drain_latency(struct drm_device *dev,
> >
> > static void vlv_update_drain_latency(struct drm_crtc *crtc)
> > {
> > - struct drm_device *dev = crtc->dev;
> > - struct drm_i915_private *dev_priv = dev->dev_private;
> > - enum pipe pipe = to_intel_crtc(crtc)->pipe;
> > - int plane_prec, plane_dl;
> > - int cursor_prec, cursor_dl;
> > - int plane_prec_mult, cursor_prec_mult;
> > -
> > - if (vlv_compute_drain_latency(dev, pipe, &plane_prec_mult, &plane_dl,
> > - &cursor_prec_mult, &cursor_dl)) {
> > - cursor_prec = (cursor_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> > - DDL_CURSOR_PRECISION_64 : DDL_CURSOR_PRECISION_32;
> > - plane_prec = (plane_prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> > - DDL_PLANE_PRECISION_64 : DDL_PLANE_PRECISION_32;
> > -
> > - I915_WRITE(VLV_DDL(pipe), cursor_prec |
> > - (cursor_dl << DDL_CURSOR_SHIFT) |
> > - plane_prec | (plane_dl << DDL_PLANE_SHIFT));
> > + struct drm_i915_private *dev_priv = crtc->dev->dev_private;
> > + struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> > + int pixel_size;
> > + int drain_latency;
> > + enum pipe pipe = intel_crtc->pipe;
> > + int plane_prec, prec_mult, plane_dl;
> > +
> > + plane_dl = I915_READ(VLV_DDL(pipe)) & ~(DDL_PLANE_PRECISION_64 |
> > + DRAIN_LATENCY_MASK | DDL_CURSOR_PRECISION_64 |
> > + (DRAIN_LATENCY_MASK << DDL_CURSOR_SHIFT));
> > +
> > + if (!intel_crtc_active(crtc)) {
> > + I915_WRITE(VLV_DDL(pipe), plane_dl);
> > + return;
> > + }
> > +
> > + /* Primary plane Drain Latency */
> > + pixel_size = crtc->primary->fb->bits_per_pixel / 8; /* BPP */
> > + if (vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
> > + plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> > + DDL_PLANE_PRECISION_64 :
> > + DDL_PLANE_PRECISION_32;
> > + plane_dl |= plane_prec | drain_latency;
> > }
> > +
> > + /* Cursor Drain Latency
> > + * BPP is always 4 for cursor
> > + */
> > + pixel_size = 4;
> > +
> > + /* Program cursor DL only if it is enabled */
> > + if (intel_crtc->cursor_base &&
> > + vlv_compute_drain_latency(crtc, pixel_size, &prec_mult, &drain_latency)) {
> > + plane_prec = (prec_mult == DRAIN_LATENCY_PRECISION_64) ?
> > + DDL_CURSOR_PRECISION_64 :
> > + DDL_CURSOR_PRECISION_32;
> > + plane_dl |= plane_prec | (drain_latency << DDL_CURSOR_SHIFT);
> > + }
> > +
> > + I915_WRITE(VLV_DDL(pipe), plane_dl);
> > }
> >
> > #define single_plane_enabled(mask) is_power_of_2(mask)
> > --
> > 1.7.9.5
> >
> > _______________________________________________
> > Intel-gfx mailing list
> > Intel-gfx@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>
> --
> Ville Syrjälä
> Intel OTC
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch