[PATCH] drm/i915: Implement Dbuf overlap detection feature starting from LNL

Govindapillai, Vinod vinod.govindapillai at intel.com
Tue Oct 29 10:24:26 UTC 2024


On Tue, 2024-10-29 at 12:13 +0200, Jani Nikula wrote:
> On Tue, 29 Oct 2024, Vinod Govindapillai <vinod.govindapillai at intel.com> wrote:
> > From: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> > 
> > From LNL onwards there is a new hardware feature, which
> > allows to detect if the driver wrongly allocated DBuf
> > entries and they happen to overlap. If enabled this will
> > cause a specific interrupt to occur.
> > We now handle it in the driver, by writing correspondent
> > error message to kernel log.
> > 
> > v2: Initialize dbuf overlap flag in runtime_defaults (Jani Nikula)
> > 
> > v3: Unmask the overlap detection interrupt (Uma)
> > 
> > v4: use display over i915 (Jani Nikula)
> > 
> > Bspec: 69450
> > Signed-off-by: Stanislav Lisovskiy <stanislav.lisovskiy at intel.com>
> > Signed-off-by: Vinod Govindapillai <vinod.govindapillai at intel.com>
> > ---
> >  drivers/gpu/drm/i915/display/intel_display_device.c |  5 +++++
> >  drivers/gpu/drm/i915/display/intel_display_device.h |  2 ++
> >  drivers/gpu/drm/i915/display/intel_display_irq.c    | 10 ++++++++++
> >  drivers/gpu/drm/i915/i915_reg.h                     |  2 ++
> >  4 files changed, 19 insertions(+)
> > 
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_device.c
> > b/drivers/gpu/drm/i915/display/intel_display_device.c
> > index aa22189e3853..16e048b83014 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_device.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_device.c
> > @@ -1227,6 +1227,7 @@ static const struct intel_display_device_info xe2_lpd_display = {
> >         .__runtime_defaults.fbc_mask =
> >                 BIT(INTEL_FBC_A) | BIT(INTEL_FBC_B) |
> >                 BIT(INTEL_FBC_C) | BIT(INTEL_FBC_D),
> > +       .__runtime_defaults.has_dbuf_overlap_detection = true,
> >  };
> >  
> >  static const struct intel_display_device_info xe2_hpd_display = {
> > @@ -1668,6 +1669,10 @@ static void __intel_display_device_info_runtime_init(struct
> > drm_i915_private *i9
> >                 if (IS_DISPLAY_VER(i915, 10, 12) &&
> >                     (dfsm & GLK_DFSM_DISPLAY_DSC_DISABLE))
> >                         display_runtime->has_dsc = 0;
> > +
> > +               if (DISPLAY_VER(display) >= 20 &&
> > +                   (dfsm & XE2LPD_DFSM_DBUF_OVERLAP_DISABLE))
> > +                       display_runtime->has_dbuf_overlap_detection = false;
> >         }
> >  
> >         if (DISPLAY_VER(i915) >= 20) {
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_device.h
> > b/drivers/gpu/drm/i915/display/intel_display_device.h
> > index 071a36b51f79..6bf5672d874d 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_device.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_device.h
> > @@ -125,6 +125,7 @@ enum intel_display_subplatform {
> >  #define HAS_CDCLK_SQUASH(i915)         (DISPLAY_INFO(i915)->has_cdclk_squash)
> >  #define HAS_CUR_FBC(i915)              (!HAS_GMCH(i915) && IS_DISPLAY_VER(i915, 7, 13))
> >  #define HAS_D12_PLANE_MINIMIZATION(i915) (IS_ROCKETLAKE(i915) || IS_ALDERLAKE_S(i915))
> > +#define HAS_DBUF_OVERLAP_DETECTION(__i915) (DISPLAY_RUNTIME_INFO(__i915)-
> > >has_dbuf_overlap_detection)
> >  #define HAS_DDI(i915)                  (DISPLAY_INFO(i915)->has_ddi)
> >  #define HAS_DISPLAY(i915)              (DISPLAY_RUNTIME_INFO(i915)->pipe_mask != 0)
> >  #define HAS_DMC(i915)                  (DISPLAY_RUNTIME_INFO(i915)->has_dmc)
> > @@ -232,6 +233,7 @@ struct intel_display_runtime_info {
> >         bool has_hdcp;
> >         bool has_dmc;
> >         bool has_dsc;
> > +       bool has_dbuf_overlap_detection;
> >  };
> >  
> >  struct intel_display_device_info {
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_irq.c
> > b/drivers/gpu/drm/i915/display/intel_display_irq.c
> > index a4f42ed3f21a..b08e9301d63e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_irq.c
> > +++ b/drivers/gpu/drm/i915/display/intel_display_irq.c
> > @@ -902,6 +902,13 @@ gen8_de_misc_irq_handler(struct drm_i915_private *dev_priv, u32 iir)
> >         struct intel_display *display = &dev_priv->display;
> >         bool found = false;
> >  
> > +       if (HAS_DBUF_OVERLAP_DETECTION(display)) {
> > +               if (iir & XE2LPD_DBUF_OVERLAP_DETECTED) {
> > +                       drm_warn(&dev_priv->drm,  "DBuf overlap detected\n");
> 
> Here too display->drm instead of &dev_priv->drm.
> 
> I'm sure this feels like nitpicking, but the point is, *all* of these
> will have to be converted to display->drm sooner rather than
> later. Adding new ones to convert is just extra churn.

Ah.. sorry! My bad! I missed that! I will fix that!

BR
Vinod

> 
> > +                       found = true;
> > +               }
> > +       }
> > +
> >         if (DISPLAY_VER(dev_priv) >= 14) {
> >                 if (iir & (XELPDP_PMDEMAND_RSP |
> >                            XELPDP_PMDEMAND_RSPTOUT_ERR)) {
> > @@ -1789,6 +1796,9 @@ void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
> >                         de_port_masked |= DSI0_TE | DSI1_TE;
> >         }
> >  
> > +       if (HAS_DBUF_OVERLAP_DETECTION(display))
> > +               de_misc_masked |= XE2LPD_DBUF_OVERLAP_DETECTED;
> > +
> >         if (HAS_DSB(dev_priv))
> >                 de_pipe_masked |= GEN12_DSB_INT(INTEL_DSB_0) |
> >                         GEN12_DSB_INT(INTEL_DSB_1) |
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 405f409e9761..327d1aa3f211 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -2589,6 +2589,7 @@
> >  #define  GEN8_DE_MISC_GSE              REG_BIT(27)
> >  #define  GEN8_DE_EDP_PSR               REG_BIT(19)
> >  #define  XELPDP_PMDEMAND_RSP           REG_BIT(3)
> > +#define  XE2LPD_DBUF_OVERLAP_DETECTED  REG_BIT(1)
> >  
> >  #define GEN8_DE_MISC_IRQ_REGS          I915_IRQ_REGS(GEN8_DE_MISC_IMR, \
> >                                                       GEN8_DE_MISC_IER, \
> > @@ -2894,6 +2895,7 @@
> >  #define   SKL_DFSM_PIPE_C_DISABLE      (1 << 28)
> >  #define   TGL_DFSM_PIPE_D_DISABLE      (1 << 22)
> >  #define   GLK_DFSM_DISPLAY_DSC_DISABLE (1 << 7)
> > +#define   XE2LPD_DFSM_DBUF_OVERLAP_DISABLE     (1 << 3)
> >  
> >  #define XE2LPD_DE_CAP                  _MMIO(0x41100)
> >  #define   XE2LPD_DE_CAP_3DLUT_MASK     REG_GENMASK(31, 30)
> 



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